Journals >Chinese Journal of Lasers
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2008
Volume: 35 Issue s2
84 Article(s)
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Research Article
Research by Simulation on the Output Power Characteristic of Superfluorescent Source Based Giles Model
Chang Cun, Yang Jiuru, and Ye Hongan
In the theoretic research of the superfluorescent source (SFS), the classic methods have some drawbacks such as high complexity and low stability. Comparatively, due to low complexity, good stability and quick convergence, the Giles model is widely applied into the theoretic research of the erbium-doped fiber amplifierIn the theoretic research of the superfluorescent source (SFS), the classic methods have some drawbacks such as high complexity and low stability. Comparatively, due to low complexity, good stability and quick convergence, the Giles model is widely applied into the theoretic research of the erbium-doped fiber amplifiers (EDFAs). Considering the similar structure of them, the Giles model is first introduced into the research of the SFS. Then, by using the four/five-order Runge-Kutta method, the curves of output power of the SFS with the single-pass forward configuration are obtained with the changes of the length of EDF, the density of Er3+ ion and the pump power. And the numerical results shows that, by using Giles model, not only the characteristics of output power of the SFS is figured out accurately, but the complexity of the simulation algorithm is reduced greatly, which improves the practicability of the theoretic research method of the SFS..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 1 (2008)
Impact of Space Radiation to Semiconductor Laser
Chang Guolong, Zhou Yanping, Zhou Jianqiang, Ma Jing, Wang Lili, Du Wenhe, and Li Mi
The electron irradiation is the main part of space radiation and also the main means that we simulate space radiative environment .To study the feasibility of semiconductor lasers used in radiative environment of space, this paper studies the total dose effects through electron accelerator simulating the radiative enviThe electron irradiation is the main part of space radiation and also the main means that we simulate space radiative environment .To study the feasibility of semiconductor lasers used in radiative environment of space, this paper studies the total dose effects through electron accelerator simulating the radiative environment of space. The result shows that as the radiation dose increases, the threshold current decreases as the dose increases and the slop efficiency increases gradually before 106 rad . During the annealing process, threshold current fluctuates in the first two weeks but the overall trend is increases and after that it tends to be stable. To the semiconductor lasers which are radiated in the relatively low dose, the radiative effects on the threshold current and slop efficiency can be eliminated through the method of current compensation..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 5 (2008)
Experimental Study on Er3+/Yb3+ Co-Doped Double-Clad Fiber Amplifier
Du Weimin, Wu Bo, Hou Tianjin, and Zhou Dingfu
A 1550 nm high efficient narrow line width fiber amplifier was demonstrated. In this amplifier double-stages amplification (MOPA) structure was employed. For the 1st stage(preamplifier), a piece of 5 m Er3+ doped fiber amplifier was used to amplifier the seed laser signal to about 90 mW. And for the second-stage amplifA 1550 nm high efficient narrow line width fiber amplifier was demonstrated. In this amplifier double-stages amplification (MOPA) structure was employed. For the 1st stage(preamplifier), a piece of 5 m Er3+ doped fiber amplifier was used to amplifier the seed laser signal to about 90 mW. And for the second-stage amplifier, a piece of 15 m Er3+/Yb3+co-doped double-clad fiber amplifier which was pumped by two high power 980 nm LDs was employed to exhibit 1.97 W output with 10.8 W pump power. The conversion efficiency and slope efficiency reached 18 % and 21 % respectively, and a gain of more than 13 dB was obtained. In the experiment, a single frequency narrow line width(DFB)semiconductor laser with a pigtail was used as the seed source. The wavelength of the laser was 1.5 μm, and the output power may reached to about 10 mW. The line width of laser was measured by the delayed self-heterodyne method, The 3 dB line width of seed source and amplified laser was about 220 kHz. Under our current environment and conditions, the phenomenon that amplified laser line width was broadened was not found..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 9 (2008)
Numerical Investigation of Semiconductor Fiber Ring Laser about Generation of Polarization Chaos
Fang Nian, Shan Chao, Wang Lutang, and Huang Zhaoming
The dynamic model of the semiconductor fiber ring laser is developed and investigated numerically. A semiconductor optical amplifier (SOA) model is employed in which the self birefringence of SOA due to stress is taken into account. The integral action of the birefringence of the fiber and the PC is represented with a The dynamic model of the semiconductor fiber ring laser is developed and investigated numerically. A semiconductor optical amplifier (SOA) model is employed in which the self birefringence of SOA due to stress is taken into account. The integral action of the birefringence of the fiber and the PC is represented with a Jones matrix of linear retarder. The dynamics model was simulated with Matlab software. The ranges of the linear retardation and the azimuth of the fast axis of the linear retarder are founded, in which the ring laser can generate polarization chaos. The effect of injected current of the SOA on the generation of polarization chaos in the ring laser is explored. The simulation results of the relationships between optical powers, degrees of polarization (DOP) of fiber ring laser and currents of the SOA are consistent with the experimental results reported earlier. A conclusion is drawn that the bigger the injected current is, and the more adjacent to zero the linear retardation and the azimuth of the fast axis of the linear retarder are, the easier the semiconductor fiber ring laser generates polarization chaos with high frequency..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 13 (2008)
Q-Switched Photonics Crystal Fiber Laser Using GaAs as Saturable Absorber
Fu Shenggui, and Liu Xiaojuan
A passive Q-switched Yb-doped photonics crystal fiber(PCF) laser is demonstrated using GaAs as the saturable absorber. The PCF core has a diameter of 21 μm and an numerical aperture(NA) of 0.04, resulting in transversal single mode wave guiding for 1020～1150 nm light, ensures the good beam quality of the laser. The lasA passive Q-switched Yb-doped photonics crystal fiber(PCF) laser is demonstrated using GaAs as the saturable absorber. The PCF core has a diameter of 21 μm and an numerical aperture(NA) of 0.04, resulting in transversal single mode wave guiding for 1020～1150 nm light, ensures the good beam quality of the laser. The laser is pumped by a high power laser diode .The pumped laser is coupled to the cladding of PCF through a self-regulating coupling system. A shortest pulse duration as 80 ns was obtained with the maximum repetition rate of 6.7 kHz, when the maximum average output power of PCF laser is 5.8 W..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 19 (2008)
Research into the Terahertz Coherent Radiation Source in View of Optical Technique
Gao Runmei
Because of the unique nature of terahertz radiation and its potential applied value, the research on the generation and detection of it is increasingly flourished. At present the study of the coherent radiation of terahertz has become one of the most important frontier research topics in the field. Three main ways of tBecause of the unique nature of terahertz radiation and its potential applied value, the research on the generation and detection of it is increasingly flourished. At present the study of the coherent radiation of terahertz has become one of the most important frontier research topics in the field. Three main ways of the generation of terahertz coherent radiation are demonstrated here. The first one is optical technique, which develops from low to high frequency. Terahertz laser is the representative, like gas laser, semiconductor laser and quantum cascade laser. The second is electronic technique, which develops from high to low frequency, like microwave tube and solid microwave source. The third is photo electronic technique, whose frequency spreads from 1 THz to both sides. The technique that the ultra fast laser triggers terahertz pulse is adopted. The terahertz coherent radiation system is designed in view of optical technique. The principle of the device is vibrational-rotational transitions of gas, by means of high pressure direct current driving excited radiation and waveguide resonating cavity. Its functional gases are N2, CD4 and D2. It may generate 1.54 THz and 1.58 THz continuous output through optimization design..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 22 (2008)
All Optical AND Gate by Utilizing Fiber Optical Parametric Amplifier
Gui Lin, Zhou Zhibin, and Shao Yufeng
The all optical AND logical operation using the wavelength conversion in the fiber optical parametric amplifier (FOPA) is completed. The logical relation between idler output and two input optical waves in the FOPA is proved through the principle of wavelength conversion and the phase match condition for four types of The all optical AND logical operation using the wavelength conversion in the fiber optical parametric amplifier (FOPA) is completed. The logical relation between idler output and two input optical waves in the FOPA is proved through the principle of wavelength conversion and the phase match condition for four types of code word in two input optical waves. By solving nonlinear coupled equations numerically utilizing Runge-Kutta method, the all optical AND logical relation between output and two input optical waves in the FOPA is verified numerically, then the output power of idler in this all optical AND logic gate influenced by fiber length, the power ratio of two input optical waves and the values of two input wavelengths is investigated. These results are conducive to the optimized design of all optical AND logic gate in practice. The selection for the width of input optical pulse in 100Gbit/s all optical AND logical operation is discussed..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 26 (2008)
High Power 1.48 μm Home-Made Phosphosilicate Fiber Cascaded Raman Laser
Huang Chaohong, Wei Dong, Lin Jiali, Wang Xiaozhong, Huang Wencai, Xu Huiying, and Cai Zhiping
A high power home-made phosphosilicate fiber cascaded Raman laser pumped by 20 W/1.06μm Yb-doped double-clad fiber laser is reported. The effect of reflectivity of output couplers on the laser threshold and efficiency are investigated experimentally. The laser threshold decreases with increasing the reflectivity of outA high power home-made phosphosilicate fiber cascaded Raman laser pumped by 20 W/1.06μm Yb-doped double-clad fiber laser is reported. The effect of reflectivity of output couplers on the laser threshold and efficiency are investigated experimentally. The laser threshold decreases with increasing the reflectivity of output FBG. The maximum continuous-wave output power of 2.8 W is obtained by 25.7% output coupler while the launched pump power is 12.1 W. The corresponding slope efficiency and the conversion efficiency are about 31.3% and 23.1%, respectively. At the maximum output power, the power fluctuation at 1.48 μm in two hour is observed to be less than 5%..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 33 (2008)
Laser Induced Damage Threshold of YSZ Films Prepared by RF Magnetron Sputtering
Li Chaoyang, Xing Guangjian, Yang Yongjun, and Jiang Wei
In this study, yttrium stabilized zirconia films (ZrO2(1-0.08)Y2O3(0.08)) have been prepared by R.F. magnetron sputtering evaporation on different types of substrates. The film properties such as structure, surface properties, optical characters are studied by XRD, AFM, SEM and spectrophotometer respectively. The effecIn this study, yttrium stabilized zirconia films (ZrO2(1-0.08)Y2O3(0.08)) have been prepared by R.F. magnetron sputtering evaporation on different types of substrates. The film properties such as structure, surface properties, optical characters are studied by XRD, AFM, SEM and spectrophotometer respectively. The effect of annealing on the structure and optical properties is investigated. The results indicate the film structure undergoes from amorphous to tetragonal phase then ultimately to tetragonal and monoclinic phase with the increase of annealing temperature. AFM analysis shows the size of YSZ particles enlarges with the increase of temperature and the surface roughness is also increased. XRD results show the crystallization is accelerated with the annealing temperature. The crystal size is increased from 20.9 nm of 400 ℃ to 42.8 nm of 1100 ℃. Then the film damage threshold is measured with a nanosecond laser according to the ISO11254-1 standard. The results indicate the films structure has great influence on the laser induced damage thresholds. Compared with the results reported by EB evaporation method, the damage threshold of magnetron sputtering has been raised with a certain extent..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 37 (2008)
Space Radiation Effect on the Characters of Fiber Amplifiers for Space Optical Communication
Li Mi, Ma Jing, Tan Liying, Zhou Yanping, Yu Siyuan, Yu Jianjie, Chang Guolong, Lu Chunlian, and Che Chi
The erbium-doped optical amplifier (EDFA) and erbium-ytterbium co-doped fiber amplifier optical amplifier (EYDFA) are irradiated by 60Co to simulate the condition on the low radiation dose orbits. Then the deterioration of their characters is analyzed by comparing these two kinds of fiber amplifiers. The central waveleThe erbium-doped optical amplifier (EDFA) and erbium-ytterbium co-doped fiber amplifier optical amplifier (EYDFA) are irradiated by 60Co to simulate the condition on the low radiation dose orbits. Then the deterioration of their characters is analyzed by comparing these two kinds of fiber amplifiers. The central wavelength and half wave width of amplified signal change little in the radiation experiment, so it indicates that both of two kinds of fiber amplifiers can be applied to the inter-satellite optical communication systems. But we also find that the gain of EDFA comes down 3.91 dB, while the gain of EYDFA comes down 17.60 dB. The results indicate that ytterbium makes the antiradiation of EYDFA much worse than that of EDFA in the same radiation environment. These results also will be a good reference for space communication designers to choose the right kind of fiber amplifiers in each different system..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 42 (2008)
High-Speed Outer-Modulation Technology of High-Power Laser
Li Mingqiu, Li Hongzuo, Jiang Huilin, and Jiang Shuhua
The high-speed electro-optical modulating technology of the high-power laser is the key technology for space optical communication transmission system. This system adopts a fiber-optical coupled laser, so it has effectively decreased the spoilage of transferring medium to the laser power. In order to obtain high-power,The high-speed electro-optical modulating technology of the high-power laser is the key technology for space optical communication transmission system. This system adopts a fiber-optical coupled laser, so it has effectively decreased the spoilage of transferring medium to the laser power. In order to obtain high-power, high-speed laser modulation signal, the system adopts 1mm-diameter of the LiTaO3 electro-optical modulator. The bandwidth of the electro-optic modulator of this system is 1 GHz, and modulation type adopts the outer modulation. Moreover, in order to ensure the modulator work in the linear region and reduce the requirement to electro optical modulator drive voltage, this system uses the automatic offset control technology. It shows that the system can satisfy the requirement of 300 Mb/s laser modulating velocity and 100 mW output power by sinusoidal signal and square signal experiment..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 46 (2008)
Discrete Optical Raman Amplifier Based on Photonic Crystal Fiber
Tao Zaihong, Chang Jianhua, and Wu Xuhua
The optical design method for the wide-band fiber Raman amplifier（FRA） based on photonic crystal fiber（PCF） is presented in this paper. Power coupled equations for a multi-wavelength broadband Raman amplifier are reasonably simplified, so a simple object function is proposed. Meanwhile a new algorithm called genetic anThe optical design method for the wide-band fiber Raman amplifier（FRA） based on photonic crystal fiber（PCF） is presented in this paper. Power coupled equations for a multi-wavelength broadband Raman amplifier are reasonably simplified, so a simple object function is proposed. Meanwhile a new algorithm called genetic and simulated annealing algorithm is proposed through improving on the conventional algorithm, which is more advantageous than using the genetic algorithm or simulated annealing algorithm respectively. Two FRAs are designed using two pumps and four pumps in this paper. The simulative results verify that PCF is perfect choice of a small-sized and efficient discrete FRA..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 50 (2008)
Experiment on Improvements of the Passive Q-switch Short-Cavity Laser Near Field Using Limiting the Gain Aperture
Wang Fang, Zhu Qihua, Lin Donghui, Chen Ji, Jiang Dongbin, Huang Zheng, and Sui Zhan
It was experimentally studied the improvements of the passive Q-switch short-cavity laser diode(LD) pumping laser near field through limiting the gain aperture. The LD pumping laser that have high stability, accurate Gauss near field distribution and smooth time output pulse is developed. The laser device is the key unIt was experimentally studied the improvements of the passive Q-switch short-cavity laser diode(LD) pumping laser near field through limiting the gain aperture. The LD pumping laser that have high stability, accurate Gauss near field distribution and smooth time output pulse is developed. The laser device is the key unit to attain the miniaturized laser range finder, adoptting some techniques of novel LD pumping, gain switching, short cavity, Q-switch passively, and bonding crystal to improve the beam quality using limiting transverse mode by the gain aperture; to ensure beam output of single longitudinal mode using short cavity and passive Q-switch; to abate Q-switch time shake using gain switch. The experimental results proved the method of improving the passive Q-switch short-cavity laser near field using limiting the gain aperture is usefull..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 54 (2008)
Coherent Output of Fiber Lasers
Wang Ji, Liu Yang, Cai Hongxing, Zheng Feng, Wang Guozheng, Jin Guangyong, and Zhang Xihe
In this paper, phase-locking and coherent output of two fiber lasers is studied. Two Er3+ high-doped fiber lasers are coupled using fused fiber coupler each other. The idea to fabricate a simple resonant cavity by coupled with fused fiber coupler in front of high-reflectivity front surface reflector of fiber lasers is In this paper, phase-locking and coherent output of two fiber lasers is studied. Two Er3+ high-doped fiber lasers are coupled using fused fiber coupler each other. The idea to fabricate a simple resonant cavity by coupled with fused fiber coupler in front of high-reflectivity front surface reflector of fiber lasers is proposed, thus to realize the coherent beam combining of two fiber laser. The mutual-injection phase-locking coherent combing experiment of two fiber lasers was demonstrated, in which the locked wavelength (center wavelength is 1549.8nm, line-width is 0.08 nm), the steady interference strips and the line-width of compression were experimentally observed. The slope efficiencies of the individual laser and the laser array. When reflectivity is 70% and pump power of two fiber lasers is 145mW, the maximum combined output power of 127mW is obtained..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 57 (2008)
Fabrication of Three-Dimensional Microstructures based on 1064 nm Laser-Induced Thermoplastic Expansion
Wang Leyan, Zhang Dongxian, Wen Zhenghu, and Zhang Haijun
A novel fabrication technology of three-dimensional (3D) microstructures by 1064 nm Nd∶YAG laser irradiation is described. This technology employs an interesting phenomenon that a thermoplastic material melted by laser heating grows in liquid surrounding space. After switching off the laser irradiation, it immediately A novel fabrication technology of three-dimensional (3D) microstructures by 1064 nm Nd∶YAG laser irradiation is described. This technology employs an interesting phenomenon that a thermoplastic material melted by laser heating grows in liquid surrounding space. After switching off the laser irradiation, it immediately solidifies into a convex microstructure because of the heat release. The experimental setup of this fabrication technology has been developed, which utilizes a 1064nm Nd:YAG laser as light source, and an X-Y scanning stage to realize the relative movement between laser irradiation and thermoplastic material. Paraffin dots and lines have been manufactured with this experimental setup. The experimental results show, the width of paraffin dots is mostly determined by the size of focal spot, and their heights increase along with the extension of irradiation time or the enlargement of laser power. Initial research about the liquid temperature impacts on thermoplastic manufacturing results has been done..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 60 (2008)
Analysis of Bit Error Rate in LD Wavelength Conversion
Wang Lili, Ren Jianhua, Qiu Xiangyan, Li Yanling, and Xu Daxiong
The mutual coupling parameter was introduced into the theoretical model of semiconductor laser wavelength conversion. Based on the improved theoretical model of wavelength conversion, the bit error rate versus mutual coupling parameter was given. The simulated results demonstrated that the mutual coupling parameter depThe mutual coupling parameter was introduced into the theoretical model of semiconductor laser wavelength conversion. Based on the improved theoretical model of wavelength conversion, the bit error rate versus mutual coupling parameter was given. The simulated results demonstrated that the mutual coupling parameter depended on the powers of signal and probe lights and the wavelength space between them. The higher the mutual coupling parameter, the less the bit error rate. It was also demonstrated that with higher signal power, lower probe power and lower wavelength space between them, which means larger mutual coupling parameter, the bit error rate of wavelength conversion is minimum, the decreasing of signal light and the increasing of probe light will increase the bit error rate..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 64 (2008)
Heteroepitaxy of InP on GaAs Substrates Using Metamorphic Buffers and Strained Layer Superlattice
Wang Qi, Ren Xiaomin, Huang Yongqing, Huang Hui, and Cai Shiwei
Heteroepitaxy of InP on GaAs substrates by LP-MOCVD has been investigated experimentally. Low temperature (LT) GaAs and ultrathin LT InP buffer layers are grown at 450 ℃, which had composed the double metamorphic buffers together. In addition, In1-xGaxP/InP(x=7.4%) strained layer superlattices (SLSs) have been insertedHeteroepitaxy of InP on GaAs substrates by LP-MOCVD has been investigated experimentally. Low temperature (LT) GaAs and ultrathin LT InP buffer layers are grown at 450 ℃, which had composed the double metamorphic buffers together. In addition, In1-xGaxP/InP(x=7.4%) strained layer superlattices (SLSs) have been inserted into the normal InP epilayers. XRD curves of InP epilayers in (004) reflection have been compared under different thicknesses of LT GaAs buffer, different insertion positions and different periods of single InGaP/InP SLS. Insertion of double SLSs into InP epilayer has also been tried. In this experiment, the full width at half maximum (FWHM) values of XRD ω scan curves are only 370 arcsec and 219 arcsec for 1.2 μm and 2.5 μm-thick InP epilayers, respectively. Subsequently, 10-period In0.53Ga0.47As/InP MQW structure has been deposited on 2.5 μm-thick InP epilayer, the peak wavelength of room-temperature PL spectrum was located at 1625nm with the FWHM value of only 60 meV. Experimental results indicate that the heteroepitaxy scheme described in this paper would become a potential approach to realize the monolithic optoelectronic integration between InP and GaAs..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 68 (2008)
Power-Balance Numerical Analysis of High-Power Laser
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To investigate the effects of a number of factors on the output power balance of high-power solid-state laser facility, the power-imbalance problem of the largest solid-state laser facility which is now building in our country was preliminarily analyzed by the integrated analytic model for multi-beam laser power balancTo investigate the effects of a number of factors on the output power balance of high-power solid-state laser facility, the power-imbalance problem of the largest solid-state laser facility which is now building in our country was preliminarily analyzed by the integrated analytic model for multi-beam laser power balance which has been developed. First the setup procedure, the functional characteristics and the main algorithms of the model were introduced. Then, the integrative influence of systematic and random deviations on opower balance was analyzed by single Haan pulse. The results showed that the power imbalance of the facility can be satisfied on condition that the systematic deviations were fully compensated, and the jitter of injection energy was 3%, and the jitter of amplifier gain coefficient was 1.5%, and the jitter of doubling-crystal detuning angle was 2%. Finally, the random-deviation specification was preliminarily allocated according the numerical calculation..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 73 (2008)
Effect of Laser Repetition Frequency on the Optical Properties of ZnO Thin Films
Wang Zhaoyang, and Hu Lizhong
ZnO thin films were grown on Si(111) substrates by pulsed laser deposition (PLD) at various laser repetition frequencies in order to investigate the structural and optical properties of the films. The optical properties of the films were studied by photoluminescence spectra using a 325 nm He-Cd laser. The structural anZnO thin films were grown on Si(111) substrates by pulsed laser deposition (PLD) at various laser repetition frequencies in order to investigate the structural and optical properties of the films. The optical properties of the films were studied by photoluminescence spectra using a 325 nm He-Cd laser. The structural and morphological properties of the films were investigated by X-ray diffraction (XRD) and atom force microscope (AFM) measurements, respectively. The results suggest that films grown at 5 Hz have excellent ultravoilet (UV) emission and high-quality crystallinity. In addition, it is not as expected that the thickness of the films was in direct proportion to laser repetition frequency. The authors think that one laser pulse is not corresponding to one growth instantaneousness. There is a growth ambience containing essential components and partial pressure in the work cavity..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 78 (2008)
Theoretical Study on Slow-Light Delays Using Broadband Incoherent Pumping Source
Zheng Di, Pan Wei, Yan Lianshan, Luo Bin, Ye Jia, Yi Anlin, Jiang Ning, Ma Yanan, Zhang Jing, and Hunag Yujun
We theoretically analyze characteristics of stimulated Brillouin scattering (SBS)-based slow light using a broadband incoherent and spectrally-sliced ASE source as the pump. Different from most previous literatures where only the delay characteristics of a single pulse are investigated, we concentrate on the transmissiWe theoretically analyze characteristics of stimulated Brillouin scattering (SBS)-based slow light using a broadband incoherent and spectrally-sliced ASE source as the pump. Different from most previous literatures where only the delay characteristics of a single pulse are investigated, we concentrate on the transmission system performance when the slow light delay is incorporated. Under different spectrally sliced bandwidths and pump power levels, the output eye diagrams, the trends of the delay time and the Q factor are obtained through numerical analysis for both nonreturn-to-zero(NRZ) and return-to-zero(RZ) data formats modulated by 2.5-Gbit/s pseudo-random bit sequences. The results show that increasing the pump power and reducing the spectrally-sliced bandwidth are both beneficial to the generated delay, while the Q-factor may degrade due to more serious signal perturbation. By properly choosing the pump power and the spectrally-sliced bandwidth, we may optimize the Q-factor without sacrificing the delay time. Using a fiber Bragg grating (FBG) as the filter after the ASE source, we can easily obtain the pumping source with～GHz bandwidth therefore greatly reduce the system complexity and the cost, with the generated delay still comparable to conventional approaches..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 81 (2008)
Magnetic-Optical Absorption Spectrum in a Rashba System and Quantizing Magnetic Fields
Yang Cuihong, Xu Wen, and Zeng Zhi
The selection rules for electron-photon interaction in a two-dimensional electron gas (2DEG) in the presence of the Rashba spin-orbit interaction (RSOI) and quantizing magnetic fields in InGaAs/InAlAs-based spintronic system have been studied based on the semiclassic Boltzmann equation. As a theoretical result, two absThe selection rules for electron-photon interaction in a two-dimensional electron gas (2DEG) in the presence of the Rashba spin-orbit interaction (RSOI) and quantizing magnetic fields in InGaAs/InAlAs-based spintronic system have been studied based on the semiclassic Boltzmann equation. As a theoretical result, two absorption peaks and abroad band absorption spectrum can be observed for high-mobility samples at relatively high magnetic fields. Similar to the spin-degeneracy system, we find that electronic transitions between the neighboring Landau levels (LLs) within the same spin orientation are the main channels for optical absorption in a spin-split 2DEG. The two absorption peaks originated from the energy spectrum varying with the strength of RSOI and the magnetic fields. And the absorption spectrum can be tuned by the electron density and Rashba parameters. However, due the LLs shifting and mixing induced by the magnetic fields and RSOI, spin-flip transitions were accompanied by the absorption of the photons and the strength of the magnetic-optical absorption peak was relatively weak..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 86 (2008)
Comparison of Different Wavelength Excited Raman Spectra of Nd∶NaGd(WO4)2 and Nd∶NaLa(WO4)2 Laser Crystals
Yang Junjie, Yang Wenqin, Wu Ji, Feng Shangyuan, Chen Enguo, and Ma Tingbao
Double tungstate crystals Nd∶NaGd(WO4)2(Nd∶NGW)and Nd∶NaLa(WO4)2(Nd∶NLW) belong to the tetragonal space group I41/a, is one kind of very promising laser crystal. In this paper Raman spectra of two crystals were analyzed in terms of group space theory. Thirty-six vibration modes were acquired. Therefore, it has thirty-sDouble tungstate crystals Nd∶NaGd(WO4)2(Nd∶NGW)and Nd∶NaLa(WO4)2(Nd∶NLW) belong to the tetragonal space group I41/a, is one kind of very promising laser crystal. In this paper Raman spectra of two crystals were analyzed in terms of group space theory. Thirty-six vibration modes were acquired. Therefore, it has thirty-six free degrees. The number of vibration modes is complied with that of the free degree. The polarized Raman spectra were discerned by using two excitation wavelengths (514.5 nm and 785 nm). Although the structure of them are similar, there was a bit discrepancy between Nd∶NaGd(WO4)2 and Nd∶NaLa(WO4)2 of the Raman spectra corresponding to the radius of Nd3+, Gd3+and La3+. Through the comparison of different wavelength excited Raman spectra ,we also got several resonance Raman peaks..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 90 (2008)
Theoretical Analysis of LD End-Pumped Yb3+∶YAG Laser
Zhang Zhiqun, Huang Zhiyun, Qiu Yishen, Li Gaoming, Ma Tingbao, Chen Shuqiang, and Cui Liqiang
In this paper, the 1030nm output power of Yb3+∶YAG laser end-pumped by 940nm laser diode(LD) is studied theoretically, where the model is developed based on the quasi-three-level rate equation. The pump absorption saturation （PAS）and re-absorption of Yb3+ ion are taken into account. The results show that, the significaIn this paper, the 1030nm output power of Yb3+∶YAG laser end-pumped by 940nm laser diode(LD) is studied theoretically, where the model is developed based on the quasi-three-level rate equation. The pump absorption saturation （PAS）and re-absorption of Yb3+ ion are taken into account. The results show that, the significant re-absorption of Yb3+ ion in the lower laser level results in the high pump threshold. The loss resulted from re-absorption is affected by the medium length and the active ion concentration, and it implies that there is an optimal combination of the length and the concentration maximizing the output laser power. Pump absorption saturation makes the population of the lower pump level and the absorption coefficient decrease, and the output power is lower..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 94 (2008)
Dual-Wavelength Fiber Ring Laser for Active Sensing Based on Optical Feedback
Zhao Yi, Wang Ming, and Zhou Junping
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 100 (2008)
Analysis of Filaments in UV Optics in High Power Solid-state laser system
Zhou Lidan, Hu Dongxia, Su Jingqin, and Zhang Xiaomin
Based on nonlinear propagation of laser and frequency conversion theory, the effects of the relationship between 1ω phase and 3ω phase on 3ω near filed were studied. The results show that the B-integral corresponding to the sharp increase of 3ω near field contrast was far less than that of 1ω, even the B-integral of 1ωBased on nonlinear propagation of laser and frequency conversion theory, the effects of the relationship between 1ω phase and 3ω phase on 3ω near filed were studied. The results show that the B-integral corresponding to the sharp increase of 3ω near field contrast was far less than that of 1ω, even the B-integral of 1ω is less than 1.8 rad, 3ω near field occurs filament. This explained the unusual damage in final optics assembly(FOA) in prototype experiments of SGIII. The results plays an important role in reducing the risk of UV optics damage in FOA..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 104 (2008)
Integrating Mobile Agents and Ant Colony Algorithm for Efficient Network Connection Management in Re-routing Optical Network
Zheng Yanlei, Gu Wanyi, Huang Shanguo, Wang Ru, Lian Weihua, and Luo Pei
In large optical networks, it is important to establish a connection from source node to destination node. In the centralized network management systems, the dynamical routing information and the states messages for failure have to be shared by the “flood” mechanism in the whole networks. Obviously, this scheme is a seIn large optical networks, it is important to establish a connection from source node to destination node. In the centralized network management systems, the dynamical routing information and the states messages for failure have to be shared by the “flood” mechanism in the whole networks. Obviously, this scheme is a serious concern because the considerable “flood” packets will jam into the network. The paper tries to introduce ant colony algorithm to improve the fault recovery for routing problem. The algorithm is applied into routing computation platform for searching and recovery the impaired routes. The application of mobile agents can be as the communication entities between the management plane and data plane. They offer several benefits, such as alarms indication for failures, the refreshment of the pheromone level. Finally, full experimental data show that the fast convergence of routing information can be realized by using the proposed distributed scheme in the scene based on our routing tested..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 110 (2008)
Research on Velocity and Delay Characteristics of Solitons in Apodized Fiber Bragg Grating
Ai Fei, Wang Kuiru, Sang Xinzhu, Xin Xiangjun, and Yu Chongxiu
Based on analytic soliton solutions of nonlinear coupled-mode equations (NLCME) in a uniform fiber Bragg grating (FBG), the existence of slow grating soliton (GS) is discussed. By introducing non-relativistic, adiabatic and quantum approximation to NLCMEs in the FBG with hyperbolic tangent apodization, and assuming theBased on analytic soliton solutions of nonlinear coupled-mode equations (NLCME) in a uniform fiber Bragg grating (FBG), the existence of slow grating soliton (GS) is discussed. By introducing non-relativistic, adiabatic and quantum approximation to NLCMEs in the FBG with hyperbolic tangent apodization, and assuming the soliton as a particle with low velocity and invariant energy, the track equation of soliton is obtained. Numerical simulations of velocity and displacement of reflected soliton, slow soliton and standing soliton are carried out to analyze the controllable velocity characteristic of the GS. Results show that time delay of 2000 ns can occur in an apodized FBG with length of 50 meters and corresponding average velocity is 0.1 c/n. The influences of grating parameters and velocity and displacement of initial input pulse solitons on time delay are further discussed. By choosing proper parameters of the apodized FBG and the initial soliton pulse, GS with any velocity between 0 and c/n can be achieved, which facilitates the compact soliton-based optical Buffer..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 115 (2008)
Research on the Demodulation Techniques for the Sensing System of Fiber Grating Based on the Nios Ⅱ
Bai Junjie, Wu Ying, and Chen Nianjun
Based on Altera′s 32 bit embedded soft-core processor Nios Ⅱ, the parallel wavelength demodulation system of a four-channel distributed fiber Bragg grating sensor network was designed. The optical system and hardware circuit for demodulation system were designed specifically. Field-programmable gate array(FPGA) is the Based on Altera′s 32 bit embedded soft-core processor Nios Ⅱ, the parallel wavelength demodulation system of a four-channel distributed fiber Bragg grating sensor network was designed. The optical system and hardware circuit for demodulation system were designed specifically. Field-programmable gate array(FPGA) is the core of the hardware circuit, which can collect and process the photoelectric signal voltage transformed to rectangular voltage pulse. The hardware circuit can communicate the signal to the computer through the universal asynchronous receiver transmitter(UART) and universal serial bus(USB). The computer can display a dynamic fiber grating wavelength demodulation process and calibrate the Bragg grating center wavelength. The system can demodulate accurately hundreds of outside signals at one time. Compared with other wavelength demodulators with the same functions, it has many advantages, such as flexibility, stabilization, easy maintenance, high-speed, high-precision, and so on. The wavelength demodulation system can be used extensively in large-scale multipoint monitor engineering. At last, an example of wavelength demodulation and calibration is given and precision can reach to ± 2 pm..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 120 (2008)
Analysis of Dispersion Characteristic in Photonic Crystal Fibers Based on FDTD Method
Chang Jianhua, Li Chuanqi, and Wu Xuhua
A method based on finite difference time domain (FDTD) is applied to calculate the photonic crystal fiber (PCF). Some problems by using FDTD have been pointed out, especially the distribution of mesh and set to the properties of PML. A dual-concentric-core photonic crystal fiber based on pure silica has been analyzed bA method based on finite difference time domain (FDTD) is applied to calculate the photonic crystal fiber (PCF). Some problems by using FDTD have been pointed out, especially the distribution of mesh and set to the properties of PML. A dual-concentric-core photonic crystal fiber based on pure silica has been analyzed by the proposed method. The transmission characteristic of such PCF has been deeply numerically simulated. By adjusting the structural parameters, we designed broadband dispersion compensating PCFs (DCPCFs) with large negative dispersion values. Simulation results show that the dispersion values vary between -400 and -600 ps/(nm·km) over the C band (from 1530 to 1565 nm), which is 5 times larger than the conventional dispersion compensating fibers (DCF) with nearly equal effective mode area. It can effectively compensate for the dispersion of 25 times of its length of standard single-mode fiber (SMF) with residual dispersion below ±1.0 ps/(nm·km) over the entire C band. It is very useful of such PCFs to be applied in leap optical amplifiers with high gain and dispersion compensation functionalities in a single component..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 124 (2008)
Measurement Investigation on the Relationship between Photo-Induce Index Increment of Hydrogen Loading Fiber and Its Dose
Chen Peng, Wang Rong, Pu Tao, Lu Lin, Fang Tao, and Guo Hong
The relationship between UV photo-induce index changes of single mode hydrogen loading fiber and its dose is studied experimentally. Maximum reflectivity model and reflectivity notch bandwidth model of uniform grating are proposed respectively for different fiber grating strength caused by its dose and the influence onThe relationship between UV photo-induce index changes of single mode hydrogen loading fiber and its dose is studied experimentally. Maximum reflectivity model and reflectivity notch bandwidth model of uniform grating are proposed respectively for different fiber grating strength caused by its dose and the influence on AC result of Bragg reflectivity wavelength deviation are analyzed relatively. Results based on experiment and measurement data indicate that, when 244 nm argon ion laser emits 40 mW UV light, the curve of refractive index changes in single mode hydrogen loading fiber is exponential type (Ac=1.632×10-6 t 0.76912), exponential growth is obvious in the beginning, a very good linear region is following, and then refractive index increments reach saturated..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 128 (2008)
Adaptive Adjust for Dynamic Range of Photon Correlator
Cheng Yanting, Shen Jin, Liu Wei, and Wang Yajing
In photon correlation spectroscopy particle sizing techniques, only when the setting of the dynamic range of photon correlator matches the decay range of target scattered light intensity autocorrelation function can the autocorrelation function produced by the photon correlator reach optimum resolution. In practice, paIn photon correlation spectroscopy particle sizing techniques, only when the setting of the dynamic range of photon correlator matches the decay range of target scattered light intensity autocorrelation function can the autocorrelation function produced by the photon correlator reach optimum resolution. In practice, parameter modification is indispensable in repetitive measurements. To solve the problem, an adaptive adjust method for dynamic range of photon correlator was presented in this paper. Through the selection of original sample time and redistribution of correlator channel sample times, photon correlator dynamic range can be adaptively adjusted to match the decay range of autocorrelation function in measurements of random particle systems..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 132 (2008)
Nonlinear Error Introduced by Beam Splitters in an Interferometric Ellipsometer
Deng Yuanlong, Li Xuejin, Chai Jinlong, and Xu Gang
A heterodyne interferometric ellipsometer (IE) with two acousto-optical modulators was investigated. A single layer of transparent ITO on a glass substrate was measured; the measurement errors of film thickness and refractive index range up to 4 nm and 6%, respectively. Beam splitters are also important error sources bA heterodyne interferometric ellipsometer (IE) with two acousto-optical modulators was investigated. A single layer of transparent ITO on a glass substrate was measured; the measurement errors of film thickness and refractive index range up to 4 nm and 6%, respectively. Beam splitters are also important error sources besides laser source and polarizing optical components. The influence of the depolarization effect and misorientation of beam splitters (BSs) on ellipsometry is studied. The error model is given by using Jones Vectors; the rules between errors and the optical characteristics and misorientation of BSs are calculated. The calculation results indicate the error of film thickness measurement produced by BSs is up to several nanometers, and is approximately linear to the misorientation angle. The influence of the depolarization effect and misorientation on measurement accuracy is cross-correlated, so the error can not be eliminated by a calibration process of removing the sample out of the optical system. For obtaining subnanometers accuracy, the misorientaion angle must be lower than 0.01°. The rules between the depolarization parameters and the nonlinear errors presented in this paper could be used to determine how to design or select beam splitters in a heterodyne interferometric ellipsometer..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 137 (2008)
A Compact Near Infrared Spectrometer Based on Fiber Fabry-Perot Filter
Ding Hui, Wu Xiangnan, and Liang Jianqi
A kind of compact near infrared spectrometer based on fiber Fabry-Perot (FFP) Filters is proposed in this paper. In order to reduce the nonlinearity and hysteresis effects of FFP and realize wavelength measurement accurately, a group of fiber Bragg gratings(FBGs) with fixed center wavelength are employed as a wavelengtA kind of compact near infrared spectrometer based on fiber Fabry-Perot (FFP) Filters is proposed in this paper. In order to reduce the nonlinearity and hysteresis effects of FFP and realize wavelength measurement accurately, a group of fiber Bragg gratings(FBGs) with fixed center wavelength are employed as a wavelength reference. Particle swarm optimization (PSO) algorithm is employed in finding the peak positions of FBGs accurately. On the base of that, polynomial fit is employed to model wavelength-voltage relationship of FFP online in each scanning cycle. Hence a kind of a compact near infrared spectrometer has been designed. Experiments have demonstrated the accuracy of wavelength measurement of the system. The range of the wavelength of the proposed spectrometer is 1490～1590 nm, the maximum absolute wavelength measurement error is as low as 0.03 nm and the spectra resolution is up to 0.4 nm..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 143 (2008)
A Novel Electrochemical Atomic Force Microscope and its Applications
Fu Xia, Xie Zhigang, Zhang Haijun, and Zhang Dongxian
A novel electrochemical atomic force microscope (EC-AFM) operating in liquid or electrolyte is developed. The special EC-AFM probe contains a tip attached a cantilever, a laser source, a position sensitive detector and a Plexiglas glass which meanwhile can be used as a tip holder. The laser optical path in liquid also A novel electrochemical atomic force microscope (EC-AFM) operating in liquid or electrolyte is developed. The special EC-AFM probe contains a tip attached a cantilever, a laser source, a position sensitive detector and a Plexiglas glass which meanwhile can be used as a tip holder. The laser optical path in liquid also owns a special design. The cantilever and the sample are immersed in fluid completely when the system works. In addition, an open electrolytic cell has been designed which enables to change the sample’s liquid environment and control the electrochemical process conveniently. Besides, when the system works, the probe tip scans over the sample surface to escape the confines of the specimen size and weight. Using the EC-AFM system, the experiment of copper plating on an iron plate in copper sulfate solution is carried out and real-time investigated. During the plating process, the AFM images of the sample surface are acquired directly in the copper sulfate with nano-scale resolution. The results show that the EC-AFM system can observe the solid-liquid interface of the electrochemical reactions and processes directly..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 147 (2008)
Polarization-dependent Loss Characteristic of 45° Tilted Fiber Bragg Gratings
Fu Shenggui, and Liu Xiaojuan
A 45°tilted fiber Bragg grating (TFBG) is fabricated in photosensitive fiber successfully using the scanning phase mask technique and a Ar-ion laser source. In order to increase the TFBG’s length and its polarization-dependent loss (PDL) effect, a concatenating technique is used in the fabricating process, keepingA 45°tilted fiber Bragg grating (TFBG) is fabricated in photosensitive fiber successfully using the scanning phase mask technique and a Ar-ion laser source. In order to increase the TFBG’s length and its polarization-dependent loss (PDL) effect, a concatenating technique is used in the fabricating process, keeping the uniform structure of the whole grating. The PDL characteristic of the TFBG is experimentally researched in the paper. Using a 45°TFBG as the polarization element, a single-polarized Er-doped fiber laser is demonstrated The polarization-extinction ratio of the output laser is about 30 dB, indicating the high PDL of the 45°TFBG. 45°TFBGs have the advantages of in-fiber, compact, good polarization capability and low price used as polarization devices..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 151 (2008)
A Side-Pump Fiber Coupler for High-Power Fiber Amplifiers
Huang Bangcai, Zhang Peng, Duan Yunfeng, and Ning Ding
A kind of side-pump fiber coupler for high-power fiber amplifiers is reported. Using the fused taper technics and a basic 2x1 coupling method, the side-pump fiber coupler of high coupling efficiency and high isolation was realized. Through the investigation of different fibers of the side-pump fiber couplers, the doublA kind of side-pump fiber coupler for high-power fiber amplifiers is reported. Using the fused taper technics and a basic 2x1 coupling method, the side-pump fiber coupler of high coupling efficiency and high isolation was realized. Through the investigation of different fibers of the side-pump fiber couplers, the double-clad fiber with outside diameter 125 μm and numerical aperture(NA)0.46 was the best selection for the signal transmission and pump launched fiber. The side-pump fiber coupler integrating a 74% pump coupling efficiency, 95% signal transmission, with exceeding 50dB isolation between the signal input end and pump-light input end and 20 dB isolation between the pump-light input end and the signal output end was obtained. Using the side-pump fiber coupler, the narrow line-width all-fiber amplifier with an output power exceeding 1W was demonstrated..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 155 (2008)
Influence Factors on Channel Number of 1D PC Polarization Filter
Shi Jianping, Huang Yuan, Dong Kexiu, and Qu Jun
Photonic crystal (PC) polarization filter is a new kind of filter that can control the polarization state of the signal light by using the photonic band gap. It has important applications in optical fiber communication, optical sensing measurements, optical information processing and other fields. The channel number isPhotonic crystal (PC) polarization filter is a new kind of filter that can control the polarization state of the signal light by using the photonic band gap. It has important applications in optical fiber communication, optical sensing measurements, optical information processing and other fields. The channel number is an important parameter for polarization filter design. The more the channel number is, the greater the information capacity is. So it is conducive to system miniaturization. The influenced factors on channel number of 1D PC polarization filter are studied by using the optical transmission matrix method, the results show that: (1) The defect layer thickness is the key factor in affecting the channel number, and channel number N is a approximate linear function of the thickness D. In the wavelength band from 500 nm to 650 nm the function is N= 0.0035D+0.159; (2) The change of refractive index in defect layer also leads to the change of channel number, and the greater the refractive index is, the more the channel number is. (3) The changes of the numbers and the thickness of photonic crystal periodic layer cannot affect the channel number, however it can regulate the central wavelength of filter channels and influence the polarization degree and separation degree of polarization..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 158 (2008)
Broad Omnidirectional High-Precision Filters Design Using Genetic Algorithm
Cui Ji, Jia Wei, Jiang Liyong, Yuan Jun, and Li Xiangyin
A photonic heterostructure, described as (B′A′)N(A′B′)N (B″A″)N(A″B″)N, is applied to design one dimensional (1D) omnidirectional filters. Using the transmission matrix method, we have investigated the transmission property of such structure, while the genetic algorithm is as well adopted to make an optimization for diA photonic heterostructure, described as (B′A′)N(A′B′)N (B″A″)N(A″B″)N, is applied to design one dimensional (1D) omnidirectional filters. Using the transmission matrix method, we have investigated the transmission property of such structure, while the genetic algorithm is as well adopted to make an optimization for different periodic number and thickness ratios in the heterostructure. Finally, we got a relatively good 1D photonic filter, which not only has relatively broad omnidirectional filter bandwidth but also presents perfect performance in direction-selection. As a high-precise omnidirectional photonic filter, it can be widely used in filters, optical switches and many other optical telecommunication areas..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 163 (2008)
PPMgLN Based High Power Optical Parametric Oscillator Pumped by a Pulsed Yb Fiber Laser
Jiang Peipei, Cai Shuangshuang, Shen Yonghang, and Wu Bo
The work on the development of a high power linearly polarized pulsed Yb fiber laser and a PPMgLN-based optical parametric oscillator (OPO) pumped by the fiber laser is introduced. The fiber laser was set as a MOPA structure which used an acousto-optic Q-switched Nd∶YVO4 laser as the seed and a Liekki large diameter PMThe work on the development of a high power linearly polarized pulsed Yb fiber laser and a PPMgLN-based optical parametric oscillator (OPO) pumped by the fiber laser is introduced. The fiber laser was set as a MOPA structure which used an acousto-optic Q-switched Nd∶YVO4 laser as the seed and a Liekki large diameter PM double clad fiber as the gain medium. A near fundamental mode laser emission at 1064 nm was obtained from the fiber laser, which delivers a maximum power output of about 17 W at a repetition rate of 50 kHz, with duration of 60 ns, polarization extinction ratio of greater than 10 dB. Using this fiber laser as the pump source to pump a PPMgLN- based OPO, high parametric conversion was achieved in the OPO. At the signal wavelength of 1518 nm, the maximum parametric output was over 9 W with 2.4 W at 3.5 micron when pumped under 16.2 W. The conversion efficiency of the OPO was 58% with a slope efficiency of 68%. At the wavelength of 1491 nm , the maximum parametric output was over 6.6 W with over 2 W at 3.7 micron when pumped under 14 W..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 168 (2008)
Refractive Index Sensing of Cascaded Long-Period Fiber Gratings with Film Coating
Jiang xiuli, and Gu zhengtian
Cascaded long-period fiber gratings (CLPFGs) with film coating is highly sensitive to the film refractive index and surrounding refractive index, so it can be used as gas sensor or solution concentration sensor. The ratio between the relative change of interference peak wavelength of CLPFGs with film coating and relatiCascaded long-period fiber gratings (CLPFGs) with film coating is highly sensitive to the film refractive index and surrounding refractive index, so it can be used as gas sensor or solution concentration sensor. The ratio between the relative change of interference peak wavelength of CLPFGs with film coating and relative change of the film refractive index, and the ratio between the relative change of interference peak wavelength of CLPFGs with film coating and relative change of the surrounding refractive index under different film thickness are numerically calculated using couple-mode theory and transfer matrix method. By choosing appropriate film thickness, we can obtain higher sensitivity. Data simulation shows that the sensitivity to film refractive index and surrounding refractive index is predicted to be 10-5..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 172 (2008)
Negative Refraction in Two-dimensional Photonic Crystal with Ring-shaped Holes
Kong Lingkai, Zheng Zhiqiang, Feng Zhuohong, Jiang Cuihua, and Ming Hai
Negative refraction in two-dimensional photonic crystal with ring-shaped holes is studied by the plane wave expansion method and the finite difference time domain method. The band structure and the equifrequency contours of the two-dimensional photonic crystal with ring-shaped holes in triangular lattices are caculatedNegative refraction in two-dimensional photonic crystal with ring-shaped holes is studied by the plane wave expansion method and the finite difference time domain method. The band structure and the equifrequency contours of the two-dimensional photonic crystal with ring-shaped holes in triangular lattices are caculated. Based on the analysis of the band structure, the equifrequency contours the relationship between the normalized frequencies and the effective refraction indices are given. Negative refraction in planar slab and wedge structure with the effective refraction index n=-1 is simulated by the finite difference time domain method. The results show that it′s easier to realize negative refraction in photonic crystal with ring-shaped holes, and the parameters of the structure are tolerant. A lot of time can be saved during the fabrication processes by the X-ray lithography..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 178 (2008)
The Investigation of anti-Stokes lines in the Index-guiding photonic crystal fiber
Liang Danhua, Hou Lantian, Gao Fei, Wang Wei, and Wang Fuzeng
A photonic crystal fiber(PCF) with zero dispersion wavelength around 800 nm is designed and fabricated. The simulated results show that the zero dispersion wavelength of fundamental mode of the PCF is at 825 nm and FMW is possible in fundamental mode. Anti-Stokes line around 610 nm can be generated efficiently with 810A photonic crystal fiber(PCF) with zero dispersion wavelength around 800 nm is designed and fabricated. The simulated results show that the zero dispersion wavelength of fundamental mode of the PCF is at 825 nm and FMW is possible in fundamental mode. Anti-Stokes line around 610 nm can be generated efficiently with 810nm 200 fs Ti∶Sapphire laser used as pump. The output signal has a Gauss like field, which indicats that anti-Stokes signal is in the fundamental mode of PCF. The output energy of anti-Stokes signal is much more than the energy of residual pump laser. The maximum ratio of the anti-Stokes signal energy to the pump component in the output spectrum is estimated as 1.2 and the conversion efficiency is above 50%, wavelength conversion is achieved commendably..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 184 (2008)
Effect of Birefringence Property of Crystal on Angle-Tunable Curve
Lu Yimin, Zhang Wei, and Wang Kewei
Using the type Ⅰ matching mode of negative uniaxial crystal and with the microanalysis method, the angle-tunable curve that indicates the connection between wavelength increment of signal light and phase matching angle is studied. Under the condition of a little of phase-matching angle-variety, the proximate angle-tunaUsing the type Ⅰ matching mode of negative uniaxial crystal and with the microanalysis method, the angle-tunable curve that indicates the connection between wavelength increment of signal light and phase matching angle is studied. Under the condition of a little of phase-matching angle-variety, the proximate angle-tunable curve is gained. After constructing a function which is token of intensity of the birefringence property, principally, the relation between the birefringence property of crystal and wavelength-tunable sensitivity relative to increment of phase matching angle is discussed. The result shows that the angle-tunable curve is very sensitive when the birefringence property of crystal is stronger..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 188 (2008)
Michelson Interferometer Based on Self-Collimation in a Two-Dimensional Rod-Type Photonic Crystal
Ni Bo, Li Hui, Chen Xiyao, Qiu Yishen, Chen Shuqiang, and Bai Jibo
A theoretical model of Michelson interferometer in a two-dimensional rod-type photonic crystal (PhC), is proposed and numerically demonstrated. The MI includes one splitter and two mirrors. Lights propagate between them independence on self-collimation effect. The two interferometer branches have different path lengthsA theoretical model of Michelson interferometer in a two-dimensional rod-type photonic crystal (PhC), is proposed and numerically demonstrated. The MI includes one splitter and two mirrors. Lights propagate between them independence on self-collimation effect. The two interferometer branches have different path lengths. By using the finite-difference time-domain method, the calculation results show that the transmission spectra at the output ports are in the shape of sinusoidal curves and have a uniform peak spacing in the frequency range from 0.192c/a to 0.200c/a. When the path length of the longer branch is increased and the shorter one is fixed, the peaks shift to the lower frequencies and the peak spacing decreases nonlinearly. For the operating wavelength around 1550 nm, the whole structure is about tens of microns .So it may be applied in future photonic integrated circuits..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 192 (2008)
Research of the Effect of the Linear Birefringence on the Performance of FBG Sensor For Measuing Magnetic Field
Peng Hui, Su Yang, and Li Yuquan
The methods of electromagnetic sensor with fiber grating based on the polarized effect were discussed. The effect of the linear birefringence and the incident polarizing angle on the output performance of the sensor were derived using Jones matrix and the simulations were made. The research on the relationship between The methods of electromagnetic sensor with fiber grating based on the polarized effect were discussed. The effect of the linear birefringence and the incident polarizing angle on the output performance of the sensor were derived using Jones matrix and the simulations were made. The research on the relationship between the sensitivity of the sensor to the linear birefringence and the incident polarizing angle has been made. The results show that when incident polarizing angle has some special values the sensitivity of the system to the linear birefringence will be minimized and the stability of the system will be enhanced..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 196 (2008)
Microring Resonator Optical Switch for Ultralow-Latency Interconnections
Tang Jianxiong, Jin Yaohui, Gao Yu, and Hu Weisheng
As a new solution raised in recent years of optical switches, Semiconductor microring resonator device has its advantages in low-power consumption, ultralow-latency, ultracompactness. Other research groups have proposed many valuable schemes on microring resonator optical switch. We analyzed the characteristic of the mAs a new solution raised in recent years of optical switches, Semiconductor microring resonator device has its advantages in low-power consumption, ultralow-latency, ultracompactness. Other research groups have proposed many valuable schemes on microring resonator optical switch. We analyzed the characteristic of the microring resonator based on its theory and structure. Depending on the latest research progress, we introduce the use of the microring resonator as switches. We also discuss the emphasis which need to be further improved and the perspective of the microring resonator as ultralow-latency optical switches..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 200 (2008)
A Novel Design of Index-guiding Photonic Crystal Fiber with Flattened Dispersion
WANG Jingyuan, Chen Han, Wang Rong, Wen Ke, Zhu Yong, and Xu Zhiyong
Index-guiding triangular PCF with air core is proposed which guides light by total internal reflection (TIR) when the air core is smaller than the air holes in cladding. Dispersion property is investigated using full-vectorial plane-wave expansion (PWE) method. The impacts of the air core on the dispersion property areIndex-guiding triangular PCF with air core is proposed which guides light by total internal reflection (TIR) when the air core is smaller than the air holes in cladding. Dispersion property is investigated using full-vectorial plane-wave expansion (PWE) method. The impacts of the air core on the dispersion property are demonstrated and PCF with dispersion values between -10±0.5 ps/（nm·km） from 1360 nm to 1730 nm and dispersion slope between ±0.01 ps/（nm2·km） from 1370 nm to 1740 nm is obtained..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 204 (2008)
Polarizing Azimuth Angle Effect on Sensitivity of Pulsed Magnetic Field Photonic Sensors
Wang Jiangping, and Li Yuquan
The polarizing azimuth angle effect on sensitivity and the signal-to-noise ratio are theoretically analyzed in polarization pulsed magnetic field sensors. A novel scheme for improving the sensitivity of pulsed magnetic field sensors was proposed. The experimental results show the sensitivity is 1.8/T,1.9/T,2.9/T and 4.The polarizing azimuth angle effect on sensitivity and the signal-to-noise ratio are theoretically analyzed in polarization pulsed magnetic field sensors. A novel scheme for improving the sensitivity of pulsed magnetic field sensors was proposed. The experimental results show the sensitivity is 1.8/T,1.9/T,2.9/T and 4.6/T respectively when the polarizing azimuth angle is 45°, 60°, 70°and 80°,so the sensitivity can potentially be considerably improved by setup suitable for the polarizing azimuth angle. The experimental results which agree well with the theoretical analysis prove the validity of this method..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 208 (2008)
Measurement of Maximum Blazed Angle and Optimization Analysis for a Micro Programmable Blazed Grating
Wang Lanlan, Li Xiaoying, Yu Yiting, Yan Bin, and Li Taiping
As an important optical performance, the maximum blazed angle decides the applicable spectrum band for the micro programmable grating. For achieving the maximum blazed angle of the fabricated micro programmable grating, two experimental measuring methods were proposed, and a simple optical system was set up for verifyiAs an important optical performance, the maximum blazed angle decides the applicable spectrum band for the micro programmable grating. For achieving the maximum blazed angle of the fabricated micro programmable grating, two experimental measuring methods were proposed, and a simple optical system was set up for verifying their feasibility and efficiency. The measured results agree well with both the theoretical computation and numerical simulation, and the relative errors are less than 3.5%. In addition, according to the experimental phenomenon, a simulation with Matlab software was performed to analyze the influence of release holes on the diffraction pattern. It offers a technical reference for improving the optical performance of the micro programmable grating..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 211 (2008)
Calibration of the Frequency-response Function for Interferometer Based on Step-Phase Comparing Method
Wu Xuhua, Chen Lei, and Chang Jianhua
When the phase wavefront is measured by a large aperture interferometer, there are anamorphic effects on the wavefront power spectral density (PSD) with high spatial frequency. So it’s necessary to calibrate the frequency-response function of the large aperture interferometer to guarantee the precision of the testing pWhen the phase wavefront is measured by a large aperture interferometer, there are anamorphic effects on the wavefront power spectral density (PSD) with high spatial frequency. So it’s necessary to calibrate the frequency-response function of the large aperture interferometer to guarantee the precision of the testing process. In this paper, the calibration principle of the frequency-response function is mainly discussed by adopting the wavefront PSD through the theoretical and experimental methods. After the calculation model of the frequency-response function is setup, the calibration methods such as sinusoidal phase grating method and step-phase comparing method are pointed out respectively. Depending on comparison between the advantages and disadvantages of these two methods, reasonable experiment method with a step is confirmed, which feasibility to calibrate an interferometer is also discussed thoroughly, and two necessary conditions for a step sample used to do calibration are given. Based on the principle of phase comparing, a standard phase object that contained a step phase is designed and fabricated. The frequency-response function is obtained by comparing the theoretical values and the measured value of the PSD. The experiment results and curves are also given in this paper. At last, the main error sources appeared in the testing process and their influences are systemically analyzed..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 215 (2008)
Study on Spectral Characteristics of Bend Fiber Bragg Grating
Yang Li, and Deng Xiao
The spectral characteristics of bend fiber Bragg gratings (FBGs) are theoretically and experimentally investigated. A bend fiber chosen as the reference waveguide in coupled mode analysis, the analysis model for bend waveguides and the mode solvers for leaky are studied, and the quasi guided mode (actually leaky modes)The spectral characteristics of bend fiber Bragg gratings (FBGs) are theoretically and experimentally investigated. A bend fiber chosen as the reference waveguide in coupled mode analysis, the analysis model for bend waveguides and the mode solvers for leaky are studied, and the quasi guided mode (actually leaky modes) in the bend fibers are successfully solved. The influence of photoelastic effects is also taken into account during the mode searching. The variations of the spectral characteristics of bend FBG are analyzed by using coupled mode theory.The variation of Bragg wavelength is coincident with that obtained by experimental measurements . It is shown that red shift of Bragg wavelength is at the order of 10-2 nm for a common single mode fiber based bend FBG with bend radius of 1.0 cm..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 220 (2008)
Application of Finite Impulse Response Theory in the Design of Optical Interleaver
Yang Xiaowei, and Zhang Juan
Asymmetrical birefrigent crystal interleaver is designed by using digital signal processing theory. Based on Jones-matrix theory, the expression of the system composed of several cascaded crystal wave plates located between a polarizer and an analyzer is calculated, and it is simplified to make the output frequency resAsymmetrical birefrigent crystal interleaver is designed by using digital signal processing theory. Based on Jones-matrix theory, the expression of the system composed of several cascaded crystal wave plates located between a polarizer and an analyzer is calculated, and it is simplified to make the output frequency response satisfy the expression of FIR by using Z transform. Using FIR digital filter design technique, an asymmetrical interleaver is designed. The azimuth angles of crystal and analyzer are determined by using step-down iteration method based on the expression of spectral transmittance. An asymmetrical 50 GHz interleaver is designed, the ratio of one output port (narrow bandwidth) to another output port (wide bandwidth) at 3 dB passband is 1∶2. The design examples of three crystals structure using Equiripple method are given. The bandwidth at 0.5 dB passband,channel isolation and gradient in both wide port and narrow port are given. Three design results respectively got by three different FIR design methods in the same order are compared, and the advantages and drawbacks of different methods are analyzed..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 224 (2008)
A New Microprogrammable Grating and Its Potential Application
Yu Yiting, Yuan Weizheng, Wang Lanlan, Yan Bin, and Li Taiping
Based on the microelectromechanical systems (MEMS) technology, a new microprogrammable grating with its blazed angle electrostatically modulated was developed using a two-layer polysilicon surface micromachining process, which has a simple structure and a large tunable capability in its blazed angle. A pull-in voltage Based on the microelectromechanical systems (MEMS) technology, a new microprogrammable grating with its blazed angle electrostatically modulated was developed using a two-layer polysilicon surface micromachining process, which has a simple structure and a large tunable capability in its blazed angle. A pull-in voltage of 110～115 V, restoring voltage of 74～65 V, resonant frequency of ～78 kHz, adjusting time of ～12 μs, and maximum operational blazed angle of more than 5 ° were achieved. The measured results are basically consistent with the simulation. The possibility of using the new microprogrammable grating as an optical switch was discussed in detail. And a few recommendations were proposed for such application considering the existing problems of the grating..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 229 (2008)
Research on Ultra-Precision Alignment Technique Using Diffracting Gratings
Zhang Jinlong, Pan Shili, Liu Yang, Liu Jingnan, and Yoshihisa Uchida
A double diffracting gratings measurement system with the resolution of nanometer order is analyzed. A mathematic model of diffracting Moiré signal and displacement measurement is established. The displacement characteristics of laser Moiré signals are studied by numerical simulation. A precision position devA double diffracting gratings measurement system with the resolution of nanometer order is analyzed. A mathematic model of diffracting Moiré signal and displacement measurement is established. The displacement characteristics of laser Moiré signals are studied by numerical simulation. A precision position device using double diffracting gratings is designed which can achieve precise position measurement and automatic precisionalignment by the differential Moiré signal between two laser Moiré sensors. The differential Moiré positioning technique are used, which greatly improves sensitivity of position signals and positioning precision. The compound control system for precision positioning is set up using the coarse alignment and the fine alignment, which achieves the high alignment accuracy and quick alignment speed. The experimental result shows the alignment device using diffracting gratings can perform positioning accuracy of ±0.5 μm..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 233 (2008)
Range Research in Pulse-Phase Laser Rangefinder with Non-Cooperative Target
Yao Pingping, Zhang Yi, Tu Bihai, Zhao Xin, and Zhao Pingjian
In terms of range, speed, accuracy and reliability for medium range measurement with non-cooperative target, the pulse-phase laser rangefinder is superior to conventional pulsed laser rangefinder and phase-shift laser rangefinder. A high resolution ranging method is described utilizing a novel modulated waveform, hereaIn terms of range, speed, accuracy and reliability for medium range measurement with non-cooperative target, the pulse-phase laser rangefinder is superior to conventional pulsed laser rangefinder and phase-shift laser rangefinder. A high resolution ranging method is described utilizing a novel modulated waveform, hereafter referred to as coherent burst modulation. The laser is sinusoidally modulated for a brief period of time and then is off for a much longer period of time. This burst waveform has benefits compared to a continuous wave emission in that the laser peak power can be very high for measuring long distances, yet the average power can be kept low for eye safety. And more, the pre-amplified optical receiver possessing temperature compensation and feedback resistance noise compensation is designed which is based on the noise spectrum density theory of silicon avalanche-photodiode (Si-APD). The influence of background light, reverse biasing voltage and feedback resistance on the performance of APD detection circuit is analyzed in detail. The experimental results confirm that the method proposed and the optical receiver has obtained the best signal-to-noise ratio (SNR) keeping the Si-APD operating under the optimum multiplied condition and improved the detecting sensitivity and measuring distances of the pulse-phase laser rangefinder..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 237 (2008)
Supercontinuum Generation and Control from Large-Mode-Area Photonic Crystal Fiber
Zhao Lei, Zhu Qihua, Sui Zhan, Zhang Ying, Zuo Yanlei, Hao Xin, Zhou Kainan, Zeng Xiaoming, Wang Xiao, Huang Zheng, Xie Xudong, Deng Wu, and Huang Xiaojun
Large-mode-area photonic crystal fiber is used to generate high power, high beam quality supercontinuum. Propagation and supercontinuum generation process of laser pulse in large-mode-area (LMA) photonic crystal fiber (PCF) is simulated by solving the general nonlinear Schrdinger equation (GNLSE) using the split-step Large-mode-area photonic crystal fiber is used to generate high power, high beam quality supercontinuum. Propagation and supercontinuum generation process of laser pulse in large-mode-area (LMA) photonic crystal fiber (PCF) is simulated by solving the general nonlinear Schrdinger equation (GNLSE) using the split-step Fourier method. Effects of the pump pulse parameters (peak power and chirp) and the length of photonic crystal fiber used on supercontinuum generation are particularly estimated. Nonlinear spectral broadening mechanism of laser pulse in large-mode-area photonic crystal fiber is discussed. The results show that the process of supercontinuum generation can be divided into three stages: initial broadening, dramatic broadening and saturation broadening. The spectrum width and efficiency can be achieved by the optimized length of LMA PCF to insure output of the generated supercontinuum at the dramatic broadening stage. The pump peak power and chirp have important impact on supercontinuum generation. When a small peak power pump is input, the spectrum broadens symmetrically. When the pump peak power increases, it brings little changes with the shorter wavelength component but broader of the longer wavelength component. The time-domain shape of the pulse exhibits concussion modulation as the effect of pulse breakup. When the pump chirp is positive, little influence is shown, except a shift of longer wavelength power by increasing the chirp. But the full width of the supercontinuum has little changes. While the pump chirp is negative and satisfy certain condition, the nonlinear is enhanced to facilitate the supercontinuum generation..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 245 (2008)
Simulation Research on Tunable Photonic Microwave Filter Based on Reconstruction Equivalent Chirp Superstructure Fiber Bragg Grating
Zheng Jilin, Wang Rong, Li Yuquan, Pu Tao, and Guo Hong
A novel tunable photonic microwave filter based on reconstruction equivalent chirp (REC) superstructure fiber Bragg grating (SFBG) is proposed. SFBGs with different slope of group time delay can be neatly designed and fabricated using a uniform phase mask according to the REC technology. As basic time delay among taps A novel tunable photonic microwave filter based on reconstruction equivalent chirp (REC) superstructure fiber Bragg grating (SFBG) is proposed. SFBGs with different slope of group time delay can be neatly designed and fabricated using a uniform phase mask according to the REC technology. As basic time delay among taps of FIR filter, the differential group delay among SFBGs determine the free spectral range (FSR) of the filter. Thus a tunable FSR can be realized by tuning the wavelength of the tunable laser source (TLS) which determine the time-delay difference. The simulation result shows that the FSR can be continuously tuned from 21 GHz to 33 GHz. In fact, this novel tunable filter can be realized in terms of any given frequency band and tuning range in theory due to the flexibility of the REC technology..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 250 (2008)
Research on Dynamic Demodulating Technique for Fiber Grating Sensor System
Zhu Zhu, Zeng Jie, Liang Dakai, and He Ren
A dynamic-strain demodulating system based on a fiber Bragg grating (FBG) filtering is proposed and experimentally demonstrated.The FBG is glued onto the experimental laminate as smart material to monitor the structure vibration. Edge filtering of long-period fiber grating (LPFG) is used to demodulate FBG with light inA dynamic-strain demodulating system based on a fiber Bragg grating (FBG) filtering is proposed and experimentally demonstrated.The FBG is glued onto the experimental laminate as smart material to monitor the structure vibration. Edge filtering of long-period fiber grating (LPFG) is used to demodulate FBG with light intensity. Throgh the connection of data collect card and LabView software, the voltage signal is transported to computer. Through the experiment, this system have a nice performance to reflect the exciting frequency. The vibration frequency up to 3 kHz can be realized and the wavelength resolving power is 0.004 nm in minimal..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 254 (2008)
Study of the Photon Radiation and Superconductor of YBa2Cu3O7-x under the Oxygen Deficient Environment
Cheng Guosheng, Wu Xiaoqing, and Chen La
Using Janis CCS-350 refrigerator (which lowest temperature is 10 K) to provide the low temperature environment, from room temperature to 200 K, then using the vacuum pump continuously to make the oxygen in the oxygen deficiency YBa2Cu3O7-x(YBCO) sample to redistribute. The experiments show that under the anoxia conditiUsing Janis CCS-350 refrigerator (which lowest temperature is 10 K) to provide the low temperature environment, from room temperature to 200 K, then using the vacuum pump continuously to make the oxygen in the oxygen deficiency YBa2Cu3O7-x(YBCO) sample to redistribute. The experiments show that under the anoxia condition, the oxygen deficiency of the YBCO sample become worse. At the same time, the critical superconductive temperature become lower until to the normal status, and the situ photon radiation over the oxygen deficiency YBCO sample generates continuous photon conductive effect and photon induced superconductive effect, which can partly counteract the oxygen defect which induces destroy to the superconductivity. For YBCO when x is smaller then 0.1, the samples whose convert temperature Tc higher than 90 K have unobvious oxygen deficiency and photon radiation effect under the anoxia condition. It is discussed the reactions between different elements induced by photon effect in the YBCO superconductivities, under the situation that the energy gap is less than normal semiconductivities for at lest two orders, and the situation of higher photo absorption coefficients. It is helpful to the application of YBCO superconductivity and useful for understanding the mechanism of the high temperature superconductor..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 259 (2008)
Synthesis and Application of Oil-Soluble Fluorescent Dyes Based on 1,8-Naphthalimide
Guo Pu, Fan Jun, Shan Linjie, Liu Enzhou, and Hu Xiaoyun
4-bromine-1,8-naphthalic anhydride as raw material through the imidization and substitution reaction can get 4-alkoxy-N-18 alkyl-1,8-naphthalimide fluorescent compounds. The yield is as indicators to discuss the factors impacting on the imidization and the imidization process was optimized further. The reaction tempera4-bromine-1,8-naphthalic anhydride as raw material through the imidization and substitution reaction can get 4-alkoxy-N-18 alkyl-1,8-naphthalimide fluorescent compounds. The yield is as indicators to discuss the factors impacting on the imidization and the imidization process was optimized further. The reaction temperature was 50 ℃. The reaction time was 3 h. The molar ratio of 4-bromine-1,8-naphthalene anhydride and 18 amines was 1∶1.08. The yield of 4-bromine-N-18 alkyl-1,8-naphthalimide is up to 81.6%. The infrared spectra of the intermediate product showed it agreed with the requirement. The fluorescence spectra of the target products 4-alkoxy-N-18 alkyl-1,8-naphthalimide was detected. The fluorescence spectra showed that these compounds had obvious emission peak in the range of 510～550 nm wavelength when the excitation wavelength was 464 nm. Target products in the lubricants of automotive air-conditioning systems have better solubility, and they give notable green or yellow-green fluorescent in ultraviolet light exposure..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 263 (2008)
Laser-Assisted Manufacturing of Three-Dimensional Functional Accessory
Guo Ruhai, Guo Jin, Guo Lihong, and Yang Guilong
Adopting the principle of sintering of laser for manufacturing three-dimensional (3D) functionally graded accessory in this paper, by using high performance Nd∶YAG laser (wavelength 1.06 μm) and optical system, through precisely controlled nozzle to deliver metal powder, associated digital controlled substrate and beamAdopting the principle of sintering of laser for manufacturing three-dimensional (3D) functionally graded accessory in this paper, by using high performance Nd∶YAG laser (wavelength 1.06 μm) and optical system, through precisely controlled nozzle to deliver metal powder, associated digital controlled substrate and beam scanning by computer, it had been fabricate alloy steel tube accessory consist two metal powder layer by layer in focus of laser. The most difficult problem was the design and the processing of manufacturing head in this system. It had shown the mechanical structure of the manufacturing head, structural design of powder nozzle and the layout of the whole laser-assisted manufacturing system. The whole manufacturing process was through the friendly man-machine interface. Every 3D model designed by UG software was sliced into piece by piece and stacked every layer to form the steel tube on the substrate. The accessory was observed by the metallography to get its metal distribution, and then using micro-hardness instrument to check the microhardness distribution in the vertical direction. The results show that the microhardness distribution of steel tube was fully dependent on material components distribution, which verifying the usefulness of this manufacturing system to fabricate the functionally graded accessory..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 267 (2008)
Analysis and Fabrication of the Two-Dimensional Periodic Anti-Reflective Subwavelength Structure
Hao Yu, Jiang Tian, Feng Yijun, Ni Yaru, and Lu Chunhua
Compared with traditional optical multilayer coating method, the two-dimensional subwavelength periodic structure can achieve better anti-reflective effect with the easy adjustment of the whole structure’s refractive index, by varying the structural parameters, such as the size and the period. Based on the finite elemeCompared with traditional optical multilayer coating method, the two-dimensional subwavelength periodic structure can achieve better anti-reflective effect with the easy adjustment of the whole structure’s refractive index, by varying the structural parameters, such as the size and the period. Based on the finite element method of full-wave electromagnetic field analysis, we investigate the periodic subwavelength structure of closely-packed nano-particles, and study on how the geometry of the structure affects the reflectivity. We also prepare different sizes of silica nano-particles by using the sol-gel method, and fabricate anti-reflective samples with these particles. Reflection measurement of the samples showed good anti-reflective performance at optical range. Finally we propose a practical method for designing periodic antireflective subwavelength structure of nano-particles on the basis of both theoretical calculation and experimental verification..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 271 (2008)
Using Image Processing Measuring the Three-Dimensional Surface Roughness for Grinding
Hu Zhongxiang, Teng Jiaxu, Shi Xiaojun, Huo Xiaojing, and Ma Xuehong
Three-dimensional measuring method is more fuller reflect the geometry shape message of parts pattern than 2D method. 3D parameter’s statistical property and robustness are fine. A non-contact measurement method of surface roughness 3D parameters based on digital image processing is presented. 3D surface roughness measThree-dimensional measuring method is more fuller reflect the geometry shape message of parts pattern than 2D method. 3D parameter’s statistical property and robustness are fine. A non-contact measurement method of surface roughness 3D parameters based on digital image processing is presented. 3D surface roughness measuring system is established. In experiment, image information is gathered from the digital camera and is pre-processed by using median filtering, grayscale equalization and histogram conversion amplification. Taking five different surface roughness specimens of plain grinding for experiment, Mean value(m), Variance(σ),Root mean square deviation(Sq), Steep kurtosis (Sku) are calculated. Then the correlation between those parameters and roughness average (Ra) is analyzed. The results showed that m,σ, Sq are increasing along with Ra. But the exact correlation between Sku and Ra cannot be discovered..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 275 (2008)
Photonic Crystals Prepared with Sol-Gel Technique
Huang Yuanming, Deng Yuan, Zhou Fufang, and Zhai Baogai
Silicate particles are synthesized by hydrolysis of ethyl silicate in the mixed solvents of ethyl alcohol and water under the catalysis of ammonium water solution. Scanning electron microcopy and laser light scattering spectroscopy show that the synthesized silicate particles are in perfect spherical shape and are monoSilicate particles are synthesized by hydrolysis of ethyl silicate in the mixed solvents of ethyl alcohol and water under the catalysis of ammonium water solution. Scanning electron microcopy and laser light scattering spectroscopy show that the synthesized silicate particles are in perfect spherical shape and are monodispersed in sizes with their diameters of about 0.7 μm. These silicate particles can assemble themselves into photonic crystals on glass substrates. The eleventh order of diffraction can be observed when a beam of helium-neon laser is perpendicularly incident on the thin films of the photonic crystals formed by the silicate particles. Six-fold symmetric diffraction patterns are recorded when a beam of white light passes through the photonic crystals, suggesting that hexagonal close packing structure can be formed in the photonic crystal by the silicate particles..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 280 (2008)
Photocurrent of Ultraviolet Photoconductive Detectors with ZnO Thin Film
Wang Yi, Jiang Wei, Xing Guangjian, Wu Guangming, and Han Bin
ZnO thin film was prepared by direct current (DC) magnetron sputtering, whose properties were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and ultraviolet-visible spectrometer (UV-Vis). The photocurrent characteristics of the metal-semiconductor-metal (MSM) photoconductive ultraviolet deZnO thin film was prepared by direct current (DC) magnetron sputtering, whose properties were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and ultraviolet-visible spectrometer (UV-Vis). The photocurrent characteristics of the metal-semiconductor-metal (MSM) photoconductive ultraviolet detector with Au/ZnO/Au structure based on ZnO film were investigated. The results showed that ZnO UV detector had a higher photocurrent of 2.5 mA under the typical responsivity peaked at around 360 nm, the dark current was 250 μA with the applied bias of 5 V. In addition, ZnO UV detector also had a higher photocurrent at the wavelength from 250 nm to 380 nm, and photoresponse obviously reduced between 380 nm and 430 nm. And a slow photoresponse with a rise time of 20 s and a decay time of 80 s was achieved. The ratio of UV (360 nm) photoresponse to visible (450 nm) one is about three orders from the spectra response. The neutralization of photogenerated holes by negatively charged oxygen ions plays a key role in the photoconductive characteristics of ZnO films..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 284 (2008)
Upconversion Luminescence of Ho3+/Yb3+ Codoped SiO2-Al2O3-BaO-BaF2 Glass Ceramics
Li chenxia, Yu Congcong, Zhang Puyang, Kang Juan, Deng Degang, and Xu Shiqing
Ho3+/Yb3+codoped oxyfluoride silicate glass has been prepared. According to DTA studies, the as-made glass was crystallized. X-ray diffraction (XRD), absorption spectrum and up-conversion luminescence of glass ceramics were measured. The results show: Intense green (544 nm) and red (656 and 748 nm) emissions correspondHo3+/Yb3+codoped oxyfluoride silicate glass has been prepared. According to DTA studies, the as-made glass was crystallized. X-ray diffraction (XRD), absorption spectrum and up-conversion luminescence of glass ceramics were measured. The results show: Intense green (544 nm) and red (656 and 748 nm) emissions corresponding to the transitions 5F4/5S2→5I8,5F4/5S2→5I7 and 5F5→5I8 of Ho3+, respectively, were simultaneously observed at room temperature under 980 nm LD excitation. Compared to the as-made glass, the Ho3+ -Yb3+codoped transparent glass ceramics containing BaF2 nanocrystals exhibited highly efficient up-conversion luminescence. Especially, the green emission intensity greatly enhanced about nearly 347 times. The studied results indicate that the oxyfluoride silicate glass ceramics containing BaF2 nanocrystals is a kind of potential luminescence materials for upconversion green lasers..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 288 (2008)
The Electro-Optical Modulation Characteristic of New Soft Opto-electric Materials-Ionic Liquids
Li Jianxin, Yang Fulong, Zhang Qinghua, Zhang Shiguo, Li Zuopeng, Hu Xiaodong, Ye Baoxi, Zhang Xiaoping, and Deng Youquan
The electro-optic modulation characteristic of the new soft opto-electric materials-ionic liquids was firstly studied by experimental method. It is found that when the modulation signal was low-frequency AC, output optical peak power and AC signal oscillated with the same frequency. Optical power amplitude was found toThe electro-optic modulation characteristic of the new soft opto-electric materials-ionic liquids was firstly studied by experimental method. It is found that when the modulation signal was low-frequency AC, output optical peak power and AC signal oscillated with the same frequency. Optical power amplitude was found to be dependent on both AC frequency and amplitude. It increased with both the increase of AC amplitude and decrease of AC frequency. When the modulation signal was DC, it could work as an optical switch. The factors which have impact on electro-optic modulation, such as types of ionic liquids, physical size of modulator part, refractive index and electrical conductivity of ionic liquids, were also studied. Preliminarily, a possible explanation was given to the experiments..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 293 (2008)
Measuring Gas Permeability through Packaging Materials of FOLED by Mass Spectrum Technology
Li Junjian, Li Shulin, Qi Tong, and Feng Pengbin
The study on packaging materials of flexible organic light-emitting devices (FOLED) has become a hot spot of FOLED research. How to measure the transmission rates of water vapor, oxygen and other active gas through the encapsulation materials of FOLED is an important question of the FOLED packaging material research. AThe study on packaging materials of flexible organic light-emitting devices (FOLED) has become a hot spot of FOLED research. How to measure the transmission rates of water vapor, oxygen and other active gas through the encapsulation materials of FOLED is an important question of the FOLED packaging material research. A new method for measuring the gas transmission rates through packaging materials of FOLED by mass spectrum technology is provided in this paper. A mass spectrum measuring system is established for determine the permeability of the packaging materials. The principle of the measuring system is introduced. Permeation rates of water vapor, oxygen and carbon dioxide through PET plastic film, and of water vapor through ITO film and silver film were measured. The measurement results are credible by comparing the data with which other literature reported..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 297 (2008)
Investigation of Photoinitiated Harden Characteristic of the Light-Thermal Sensitive Microcapsule Material
Li Xiaowei, Lai Weidong, Li Xinzheng, and Fu Guangsheng
In this paper, the photoinitiator 184 and prepolymer TMPTA are microencapsulated based on the interfacial polymerization technique. The shape of microcapsules is uniform and the peak diameter is about 0.3 μm detected with scanning electron microscope (SEM) and laser particle diameter analyzer. The weight loss result veIn this paper, the photoinitiator 184 and prepolymer TMPTA are microencapsulated based on the interfacial polymerization technique. The shape of microcapsules is uniform and the peak diameter is about 0.3 μm detected with scanning electron microscope (SEM) and laser particle diameter analyzer. The weight loss result verifies that the microcapsules is high thermal stable with decompose temperature above 350 ℃. The photo-harden process is investigated by the absorption spectrum and infrared (IR) technique. The absorption peak is at the wavelength of 310 nm with half width about 30nm. After exposure, the remarkable reduction in absorption intensities are observed at 1620 cm-1 for the C=C stretching and the 920.1 cm-1, 837 cm-1 for the C-H stretching on the C=C molecular bond. Such a result can be ascribed that the photo-harden reaction in the microcapsule is the process of cleavage of double bond and formation of network structure. Based on the image density property under different exposure time conditions, it can be concluded that the optimal exposure time of the microcapsule material is 20 s..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 301 (2008)
Testing Big Curvature Surface of Optical Element with Zernike Polynomial Fitting Twice
Liu Jianping, Liang Liping, and Liu Guangcan
A kind of test method of optical surface with big curvature on the plane interferometer is mainly studied, the measured surface error relative to the standard plane appointed has been obtained by some pivotal techniques such as interference fringe processing, fast Fourier transform (FFT) phase distilling, phase unwrappA kind of test method of optical surface with big curvature on the plane interferometer is mainly studied, the measured surface error relative to the standard plane appointed has been obtained by some pivotal techniques such as interference fringe processing, fast Fourier transform (FFT) phase distilling, phase unwrapping and Zernike polynomial fitting, then it subtracts the standard spherical surface appointed, so the measured surface error relative to the standard sphere appointed has been obtained by reusing Zernike polynomial. On the basis, PV, RMS, N, ΔN of the measured surface error are calculated, the interference fringe formed by the measured surface relative to the standard sphere is successfully simulated. The method overcomes the disadvantages of contact test, and provides a suitable method particularly to optical surface with high precision and big curvature radius..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 305 (2008)
Influence of Thickness on the Structural and Optical Properties of Vanadium Oxide Thin Films
Wu Xiaochun, Lai Fachun, Lin Limei, Lin Lianghui, and Qu Yan
Vanadium oxide films with different thicknesses were deposited on quartz substrates at room temperature by a thermal evaporation system. The structure and morphology of the vanadium oxide films were investigated by X-ray diffraction, Raman spectra and atomic force microscopy(AFM), respectively. Transmittances of the fiVanadium oxide films with different thicknesses were deposited on quartz substrates at room temperature by a thermal evaporation system. The structure and morphology of the vanadium oxide films were investigated by X-ray diffraction, Raman spectra and atomic force microscopy(AFM), respectively. Transmittances of the films were measured by spectrophotometer. Refractive indices, extinction coefficients and band gap of the films were calculated from all transmittance data. The experimental results show that the structure of the samples is amorphous phase. The main chemical composition of the films is V2O5 and it contains a little of VO2. All pellets on the film surface stick together, the surface roughness and surface grain size decrease with the thickness increasing. In addition, when the thickness of the film increases from 200 to 450 nm, the refractive index increases but extinction coefficient decreases, and the band gap energy decreases from 2.67 eV to 2.45 eV..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 311 (2008)
The growth of Si1-yCy Alloy on 6H-SiC homoepitaxial Layers
Yu Fei, Wu Jun, Han Ping, Wang Ronghua, Ge Ruiping, Zhao Hong, Yu Huiqiang, Xie Zili, Xiu Xiangqian, Xu Xiangang, Zhang Rong, and Zheng Youdou
Si1-yCyalloy has been deposited on SiC homoepitaxial layer acquired by chemical vapor deposition method on 6H-SiC substrates. X-ray diffraction, scanning electron microscopy, Ranman shift and other methods were applied to characterize the Si1-yCyalloy samples, and the crystal structure of Si1-yCyalloy is mainly focusedSi1-yCyalloy has been deposited on SiC homoepitaxial layer acquired by chemical vapor deposition method on 6H-SiC substrates. X-ray diffraction, scanning electron microscopy, Ranman shift and other methods were applied to characterize the Si1-yCyalloy samples, and the crystal structure of Si1-yCyalloy is mainly focused on. The results are: The Si1-yCyalloy has good surface morphology and the XRD spectrum shows only a single characteristic diffraction peak ( 2θ≈28.5°), the crystal type is 4H;it′s roughly estimated that the carbon occupis about 3.7% of all. Raman spectrum shows as C/Si ratio increases, the partition of substitute C increases, and when C/Si increases to some extent, the unsubstitute C breaks the rythm structure of the alloy, and the quality of Si1-yCyalloy turns bad..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 316 (2008)
Measurement of Plane Grinding Surface Roughness Based on Machine Vision
Shi Xiaojun, Zhang Xiaohui, Hu Zhongxiang, and Teng Jiaxu
Based on the machine vision technique, a method for measuring the three-dimensional parameters of plane grinding surface roughness is put forward for fast and on-line roughness measurement on plane grinding surface. In this method, the plane grinding surface image with Ra ranging from 0.1 to 1.6 μm is acquired by CCD aBased on the machine vision technique, a method for measuring the three-dimensional parameters of plane grinding surface roughness is put forward for fast and on-line roughness measurement on plane grinding surface. In this method, the plane grinding surface image with Ra ranging from 0.1 to 1.6 μm is acquired by CCD and stored in the computer. Firstly, the mid-value filtering, the edge strengthen and the image binary conversion are used to pre-processing the image, and then the values of plane grinding surface roughness are got through characteristic acquisition. It is proved by the initial experiment that the three-dimentional evaluation method put forward in the paper is feasible. When incident intensity is between 0.7×104～1.3×104 lux, incident angle is between 30° and 50°, root mean square value decreases with the increment of Ra. When incident angle is around 30° and Ra>0.3 μm, the kurtosis and Ra have good correlation; When incident angle is 50° and Ra>0.4 μm, the kurtosis and Ra also have good correlation..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 320 (2008)
Thermal Properties of the Material Studied by the Photoacoustic Piezoelectric Technique
Zhao Binxing, Wang Yafei, Gao Chunming, Zhou Ying, and Wang Zhanping
The thermal diffusivity of the materials has been studied by the photoacoustic piezoelectric (PAPE) technique. The thermal diffusivity of yttrium aluminum garnet (YAG) composite material has been studied. The PAPE method based on a simplified thermoelastic theory was proposed. The PAPE theory based on a simplified therThe thermal diffusivity of the materials has been studied by the photoacoustic piezoelectric (PAPE) technique. The thermal diffusivity of yttrium aluminum garnet (YAG) composite material has been studied. The PAPE method based on a simplified thermoelastic theory was proposed. The PAPE theory based on a simplified thermoelastic theory has been analyzed. The experimental system has been set up according to the simplified thermoelastic model. The experimental system was calibrated by investigating the diffusivities of many referential materials. The effective thermal diffusivity of the YAG composite material was investigated by the PAPE technique. The results were shown that the PAPE technique can be used to measure the thermal diffusivity of metal materials accurately.The measurement of YAG’s thermal diffusivity was shown that the PAPE method can effectively measure the thermal diffusivity of new composite materials in the appropriate experimental conditions..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 324 (2008)
Effect of 3/SiH4 Flow Rate Ratio on the Performance of Polysilicon/SiN Composite Solar Cell
Zhao Haofeng, Wang Ling, Xie Aigeng, Yan Kai, Wu Hongyan, Liu Bin, Huang Tingli, and Xiao Yuhui
SiN thin film has the passive role and the good nature of reducing the reflection, so it already be widely applied in the crystal silicon solar cell's fabrication technology. This paper deals with effect of NH3/SiH4 on the performance of solar cell. The test results show that NH3/SiH4 gas ratio affect the transformSiN thin film has the passive role and the good nature of reducing the reflection, so it already be widely applied in the crystal silicon solar cell's fabrication technology. This paper deals with effect of NH3/SiH4 on the performance of solar cell. The test results show that NH3/SiH4 gas ratio affect the transforming efficiency and minority carrier lifetime of solar cell and optimized NH3/SiH4 is 11.5∶1..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 328 (2008)
Optical Polarization Manipulation by Multilayered Structure of Metal-Dielectric Films
Zhao Lin, Zhao Junming, Xu Xiaofei, and Feng Yijun
By modeling the multilayered structure of metal-dielectric films as an anisotropic material based on the effective medium theory, we have theoretically analyzed the optical transmission of the structure. Optical polarization property of the proposed structure with different film orientations has been explored. The theoBy modeling the multilayered structure of metal-dielectric films as an anisotropic material based on the effective medium theory, we have theoretically analyzed the optical transmission of the structure. Optical polarization property of the proposed structure with different film orientations has been explored. The theoretical analysis and full-wave EM simulations based on the finite element method show that, in the lossless case, transmission for a normal incident TE wave is quite different from the transmission for a TM wave by adjusting the material parameters and the film orientation of the proposed structure. The result shows that the structure has property of optical polarization manipulation. Based on this particular property, we propose a multilayer structure composed of alternating silicon carbide and silicon dioxide films for polarization beam splitter at wavelength of 10.6 μm. We believe that the optical property of this metal-dielectric multilayered structure could provide a new way for the polarization manipulating of the optical devices..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 331 (2008)
IR Spectra Information Analysis of Different Tea Producing Area
Li Guang, Zhao Yanli, Zhang Rongxiang, Zhao Xiaohui, Li Xiaowei, and Zhang Lianshui
By standards testing (the sample standardization and the measure standardization), the standard IR spectras of the china famous teas were obtained. In order to investigate the overall characteristics of tea producing area, a visual, simple method (average deviation) on the IR spectra to analyze the relation between theBy standards testing (the sample standardization and the measure standardization), the standard IR spectras of the china famous teas were obtained. In order to investigate the overall characteristics of tea producing area, a visual, simple method (average deviation) on the IR spectra to analyze the relation between the average deviation and the latitude of several typical standard teas is devised. The result shows that: the average deviation of the tea with similar latitude and altitude is very small; On the contrary, the average deviation is considerable. There are affinities between the altitude and latitude of the tea producing areas and the average deviation of their IR spectrum, the average deviation is possible to be a using method to analyze the information of the tea producing area..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 335 (2008)
Detection of Heavy Metal Elements in Fume by Laser-Induced Breakdown Spectroscopy
Lin Zhaoxiang, Li Jie, Liu Linmei, Song Shuyan, and Wu Jinquan
An experimental system by laser-induced breakdown spectroscopy （LIBS）was established. The plasmas were induced by Nd∶YAG laser breakdown in fume. The emission spectra of plasmas were then dispersed by an Echelle spectrograph and detected by an intensified charge-coupled device (ICCD). Respectively, the fumes from the cAn experimental system by laser-induced breakdown spectroscopy （LIBS）was established. The plasmas were induced by Nd∶YAG laser breakdown in fume. The emission spectra of plasmas were then dispersed by an Echelle spectrograph and detected by an intensified charge-coupled device (ICCD). Respectively, the fumes from the coal combustion and firecracker combustion were detected by LIBS. The spectra have been obtained using the experimental system. A lot of heavy metal elements was detected all together by LIBS from the spectra. The calibration of line intensity versus concentration of Pb element in solid samples has been made, and the slope was linear..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 338 (2008)
Moving Object Detection and Shadow Elimination in Indoor Night Environment with Weak Lighting
[in Chinese], [in Chinese], and [in Chinese]
A novel object detection algorithm is proposed for moving object detection under weak lighting. Firstly, background model is trained for obtaining steady background image. Definition of the background and current frame image are improved by image enhancement processing. Secondly, foreground objects is got by backgroundA novel object detection algorithm is proposed for moving object detection under weak lighting. Firstly, background model is trained for obtaining steady background image. Definition of the background and current frame image are improved by image enhancement processing. Secondly, foreground objects is got by background subtracting method and the difference image is de-noised and mended. Finally, shadow in difference image is eliminated and exact moving object is got by different brightnessly between foreground, shadow and background. The effectiveness of the proposed method is demonstrated experimentally with several video clips collected in a indoor night environment..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 341 (2008)
Detection on Duck Egg′s Freshness Based on Visible Light Image Analyzing and SVM
Liu Peng, Tu Kang, Pan Leiqing, and Liu Ming
This article applied the duck egg internal visible light image information (H and I) to characterize the freshness of duck egg. The visible light image analysis technology was applied to obtain the duck egg heart color parameters. The Hafu unit was used as the confirmation index of egg freshness through experiment, theThis article applied the duck egg internal visible light image information (H and I) to characterize the freshness of duck egg. The visible light image analysis technology was applied to obtain the duck egg heart color parameters. The Hafu unit was used as the confirmation index of egg freshness through experiment, then established the forecast model based on SVM (support vector machines) which was developed using the egg heart color parameters to predicate the egg freshness. The model indicated that when we choose the SVM type as epsilon-SVR, the nuclear function as RBF ,the model characteristic parameter C=27, σ=23 ,then the model forecast effect is the best. The model forecast effect parameters RMSEC reached 0.9520, and the EMSEP reached 0.4205. The predicted value of egg freshness and the practical value has good linear correlation and predicted value has a large covering and searching ability on the practical value. This model showed better stability and confidence interval compared with the ordinary linear method. Through the comparison of SVM and neural network recognition results we can get the conclusions that SVM has a better duck-egg freshness recognition performance than ANN by egg heart color's analysis(SVM reach to 98.92%>ANN reach to 93.77%)..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 345 (2008)
MOEMS 3D Microstructure Preparation Method Based on Novel Localized Electrochemical Deposition
Ma Lihong, Zhang Haijun, Liu Chao, and Zhang Dongxian
Licalized electrochemical deposition technology is investigated based on a novel type of microelectrode and automatic control technique. The novel microelectrode is fixed on the microstepper motor. The speed of the stepper motor can be controlled. When the rate keeps the same as the deposition rate, the small gap betweLicalized electrochemical deposition technology is investigated based on a novel type of microelectrode and automatic control technique. The novel microelectrode is fixed on the microstepper motor. The speed of the stepper motor can be controlled. When the rate keeps the same as the deposition rate, the small gap between the microelectrode and the cathode will be able to basically remain unchanged. In this research, mixed electrolyte of 0.5 M/L CuSO4 and 0.38 M/L H2SO4 is selected. Cu micro column with high aspect ratio can be successfully deposited on Cu cathode from the plating solution. The aspect ratio can be greater than 7.2∶1. Micro column in diameter can be less than 120 μm. The experimental results indicate that this method can fabricate microstructures with low cost and high efficiency. It is expected that this new method will serve micro-opto-electro-mechanical systems and other micro/nano-structure preparation effectively..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 351 (2008)
Egg Freshness Detection Based on Computer Vision and BP Neural Network
Pan Leiqing, Tu Kang, Liu Peng, Zou Xiurong, and Shao Xingfeng
In order to acheieve non-destructive detection and gading of egg freshness, an experimental system was set up based on computer vision. Then egg internal substance transmission images were acquired. After pre-processing, H, S, I, a, b values were extracted. The egg shell color information (a*, b*) was also measured. AnIn order to acheieve non-destructive detection and gading of egg freshness, an experimental system was set up based on computer vision. Then egg internal substance transmission images were acquired. After pre-processing, H, S, I, a, b values were extracted. The egg shell color information (a*, b*) was also measured. And the weight of egg was measured using electronic balance and the height of egg albumen was measured using height vernier calliper. Egg freshness was calculated according to its weight and albumen height. The linear regression model for egg Hough unit and egg information (H, I, S, a, b, a*, b*, a-a*, b-b*) was established by SAS. Afterwards the 3 parameters (H, I, b) which is greatly correlated with egg freshness (HU, Egg Hough unit) was reserved. With 3 parameters (H, I, b) of input, the best BP neural network model (3 input nodes, 15 hidden nodes, 4 output nodes) was established by using Matlab. On the BP neural network model of detecting the egg freshness, the automatic detection system was designed, which can immediately show the results according to the egg′s color data after the network initialization. The results showed that the grading accuracy by using computer vision and BP neural network for egg freshness exceeds 90%..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 355 (2008)
Analyses of Microscopic Mechanism on the Interaction of THz Photon and Biomolecule System
Xu Lin, Zhang Canbang, Xu Nan, Dai Zhifu, Tian Jiajin, and Zhou Lingyun
The frequency range of THz radiation is 0.1×1012～10×1012 Hz, but the frequency of the band of biomolecule greater than 1014 Hz. Hence the interaction of THz photon with the bond of biomolecule can not lead to the resonance effects. However, according to Frohlich theory, living biomolecule system is a extreme The frequency range of THz radiation is 0.1×1012～10×1012 Hz, but the frequency of the band of biomolecule greater than 1014 Hz. Hence the interaction of THz photon with the bond of biomolecule can not lead to the resonance effects. However, according to Frohlich theory, living biomolecule system is a extreme coherence's system, its motion state poeeseees the collective vibration effect. The range of coherent vibration frequency is 0.02×1012～2.0×1012 Hz. Hence, the interaction of THz photon with the living biomolecule system can lead to the resonance effect. Under dipole approximation, the Hamiltonian of the interaction of THz photon and biosystem vibrator can take. To solute the Schrdingar equation, we can explain some fluorescence effect that are cause by THz photon’s action. Other, we discussed the mechanism on action effects of the laser photon acting to protein or cell membranes..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 361 (2008)
The Characteristic Analysis of Correlation Coefficient Array for Infrared Spectra of Tea
Zhang Rongxiang, Zhang Shihong, Li Guang, Zhao Xiaohui, and Zhang Lianshui
The application of infrared spectral on quality identification of tea is studied. The standard infrared spectra of special grade tieguanyin, special grade Longjing and fresh Pu′er typical tea are respectively measured by Fourier transform infrared spectrometer. By the visual analysis on the infrared spectra it is foundThe application of infrared spectral on quality identification of tea is studied. The standard infrared spectra of special grade tieguanyin, special grade Longjing and fresh Pu′er typical tea are respectively measured by Fourier transform infrared spectrometer. By the visual analysis on the infrared spectra it is found that the infrared absorptions of several kinds of tea can all be divided to several big areas, furthermore the spectra are similar induced by the similar of primary contents of tea. So it is difficult to visual distinguish the different spectra. In order to emphasize the contrast of character parts, better display the discrepancy of different kinds of tea, in virtue of mathematical method and computer program the array relativity of spectra is analyzed. The results show that the correlation coefficients of several kinds of tea in the region of wavenumber 1130～1570 cm-1 which belongs to the fingerprint region are smaller than the whole and other regions of wavenumber that can effectively sign the component character of tea, that is the reflected fingerprint information in this region is more obvious, the small change of structure character is more easily judged. The three kinds of tea can be distinguished by this region of wavenumber..
Chinese Journal of Lasers
- Publication Date: Aug. 13, 2021
- Vol. 35, Issue s2, 366 (2008)
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