Journals >Chinese Optics Letters
Contents
2012
Volume: 10 Issue 8
21 Article(s)
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Fiber Optics and Optical Communications
Experimental study of an ultra narrow linewidth f iber laser by injection locking
Wen Ji, Shufen Chen, Lei Fu, and Zhengfeng Zou
An ultra narrow linewidth fiber laser is presented, which is composed of a ring cavity laser and a linewidthnarrowing module. The fiber laser is introduced in detail and the single mode operation of the laser is verified. Using a revised self-heterodyne detection method, experimental data of the laser linewidth againstAn ultra narrow linewidth fiber laser is presented, which is composed of a ring cavity laser and a linewidthnarrowing module. The fiber laser is introduced in detail and the single mode operation of the laser is verified. Using a revised self-heterodyne detection method, experimental data of the laser linewidth against the pump power are presented. The narrowest linewidth is measured to be 109 Hz, whereas the output power is 1.1 mW..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 080601 (2012)
Design of tunable metal-coated long-period fiber grating filter with dispersion consideration
Yanjun Shi, and Zhengtian Gu
The design of a tunable metal-coated long-period fiber grating (LPFG) filter based on the material dispersion consideration is presented. The tuning of the resonant wavelength can be achieved by heating the metal layer. Based on the coupled mode theory, the influences of the material dispersion on the transmission specThe design of a tunable metal-coated long-period fiber grating (LPFG) filter based on the material dispersion consideration is presented. The tuning of the resonant wavelength can be achieved by heating the metal layer. Based on the coupled mode theory, the influences of the material dispersion on the transmission spectrum of the metal-coated LPFG are studied. There is a special grating period for a specific cladding mode; when the grating period is less than or equal to the special grating period, the material dispersion has weak influence on the resonant wavelength. Under such condition, the attenuation band depth corresponding to the specific cladding mode has excellent stability while the temperature changes, thus improving the filtering performances of the tunable loss filter. Further, experimental results demonstrate the validity and feasibility of the proposed tunable filter..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 080602 (2012)
Image Processing
Lightness constancy: from haze illusion to haze removal
Cheng Li, Jianzhong Wang, Qingshun Han, and Duyan Bi
The human visual system processes lightness constancy to estimate reflectance under complex viewing conditions. We focus on the underlying reason the human visual system is conscious of haze, and discuss the single-image haze-removal problem based on lightness constancy from the beginning of haze illusion. Following thThe human visual system processes lightness constancy to estimate reflectance under complex viewing conditions. We focus on the underlying reason the human visual system is conscious of haze, and discuss the single-image haze-removal problem based on lightness constancy from the beginning of haze illusion. Following the basic principle and model of "atmospheric transfer function", we bring about a simple dehazing paradigm by estimating two values using bilateral filtering. Practical investigation of parameters and design are analyzed in detail. Furthermore, a novel quantitative standard haziness presents itself naturally during the estimation process. Comparative study and objective evaluation demonstrate that the proposed method is fast and effective, yielding high-contrast and vivid haze-free images..
Chinese Optics Letters
- Publication Date: Jun. 15, 2012
- Vol. 10, Issue 8, 081001 (2012)
Imaging Systems
Quality assessment for visible and infrared color fusion images of typical scenes
Shaoshu Gao, Weiqi Jin, and Lingxue Wang
Two comprehensive evaluation metrics, image perceptual quality based on target detectability (PQTD) and perceptual quality based on scene understanding (PQSU), are proposed to measure image quality for visible and infrared color fusion images of typical scenes. A psychophysical experiment is performed to explore the reTwo comprehensive evaluation metrics, image perceptual quality based on target detectability (PQTD) and perceptual quality based on scene understanding (PQSU), are proposed to measure image quality for visible and infrared color fusion images of typical scenes. A psychophysical experiment is performed to explore the relationship between conventional quality attributes and the proposed evaluation metrics. The prediction models for PQTD and PQSU are derived by multiple linear regression statistical analyses. Results show that the variation of PQTD can be predicted by sharpness and perceptual contrast between the target and background, and that color harmony and sharpness can predict PQSU. The proposed evaluation metrics and their prediction models provide a foundation for further developing objective quality evaluation of color fusion images..
Chinese Optics Letters
- Publication Date: Jun. 15, 2012
- Vol. 10, Issue 8, 081101 (2012)
Lasers and Laser Optics
Broadband Brillouin slow light with multiple-longitudinal-mode, tunable pump
Rugang Wang, Yuejiang Song, and Xuping Zhang
We propose and demonstrate broadband Brillouin slow light using a multiple-longitudinal-mode tunable fiber laser as Brillouin pump. A tunable broadband Brillouin pump with a tuning range from 1 520 to 1 555 nm is generated using a fiber ring laser with a semiconductor optical amplifier (SOA) as its gain medium. The pumWe propose and demonstrate broadband Brillouin slow light using a multiple-longitudinal-mode tunable fiber laser as Brillouin pump. A tunable broadband Brillouin pump with a tuning range from 1 520 to 1 555 nm is generated using a fiber ring laser with a semiconductor optical amplifier (SOA) as its gain medium. The pump spectrum consists of a large number of longitudinal modes separated by 6 MHz. The 3-dB bandwidth is about 11.5 GHz, and its fluctuation is less than 100 MHz within the tuning range. An 8-Gb/s data signal can be delayed by up to 83.0 ps (bit error rate < 10 9) at 17-dBm pump power..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 081401 (2012)
Experimental research on application of Hartmann micro-lens array in coherent beam combination of two-dimensional laser array
Xiaohua Wang, Qiang Fu, Linhai Huang, Feng Shen, and Changhui Rao
We demonstrate experimentally the application of a phase error detection method in the coherent beam combination (CBC) of a laser array. The method is based on the Hartmann micro-lens array. Both the piston and tilt errors can be detected and corrected simultaneously by combining this method with adaptive optics-correcWe demonstrate experimentally the application of a phase error detection method in the coherent beam combination (CBC) of a laser array. The method is based on the Hartmann micro-lens array. Both the piston and tilt errors can be detected and corrected simultaneously by combining this method with adaptive optics-correcting technology. The far-field intensity pattern of the combined beam has high energy concentration and good beam quality. The power encircled in the main lobe of the far-field pattern is 41.3%, and the contrast of the pattern reaches 81.8%. Experimental results show the great potential of the Hartmann phasing method for use in the CBC of a large number of laser beams..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 081402 (2012)
Efficient and compact diode-end-pumped conductively cooled Q-switched Nd:YLF laser operating at 527 nm
Tingting Lu, Juntao Wang, Minjie Huang, Dan Liu, and Xiaolei Zhu
A novel, compact diode-end-pumped conductively cooled Q-switched Nd:YLF laser is developed. A diode-end-pumped pair of Nd:YLF slabs and an intracavity-frequency-doubled configuration are adopted to increase conversion efficiency. Using 49.8-mJ incident pump pulse energy at 500-Hz repetition rate, the laser obtains 11-mA novel, compact diode-end-pumped conductively cooled Q-switched Nd:YLF laser is developed. A diode-end-pumped pair of Nd:YLF slabs and an intracavity-frequency-doubled configuration are adopted to increase conversion efficiency. Using 49.8-mJ incident pump pulse energy at 500-Hz repetition rate, the laser obtains 11-mJ pulse energy and 5.5-W average output power at 527-nm wavelength, achieving an optical–optical conversion efficiency of 22%. The pulsewidth is less than 15 ns, and the beam quality factors are M2x=1.28 and M2y=1.12..
Chinese Optics Letters
- Publication Date: May. 16, 2012
- Vol. 10, Issue 8, 081403 (2012)
Coherent polarization beam combining of four polarization-maintained f iber amplif iers using single-frequency dithering technique
Pengfei Ma, Pu Zhou, Yanxing Ma, Rongtao Su, and Zejin Liu
In this manuscript, coherent polarization beam combining of four polarization-maintained fiber amplifiers is demonstrated. In each fiber amplifier, two cascaded fiber amplification stages are used to boost the output power to watt level. The compact and robust single-frequency dithering technique is employed in the actIn this manuscript, coherent polarization beam combining of four polarization-maintained fiber amplifiers is demonstrated. In each fiber amplifier, two cascaded fiber amplification stages are used to boost the output power to watt level. The compact and robust single-frequency dithering technique is employed in the active phase-locking of the four laser beams. When the system is in the closed loop, the phase noise can be suppressed effectively for long-time observation. The experimental results show that the combining efficiency of the whole system is as high as 95%..
Chinese Optics Letters
- Publication Date: May. 16, 2012
- Vol. 10, Issue 8, 081404 (2012)
Materials
Fabrication and spectroscopic properties of Yb3+-doped silica glasses using the sol-gel method
Shaojun Liu, Haiyuan Li, Yongxing Tang, and Lili Hu
Two series of Yb3+-doped silica glasses (YA and YAP) are fabricated using the sol-gel method, and their spectroscopic properties are investigated. The longest fluorescence lifetime of 0.96 ms is obtained in YAP2 and YAP3 glasses. The emission cross-section (emi) and emi × of Yb3+ in the YAP1 glass are 1.00 pm2 Two series of Yb3+-doped silica glasses (YA and YAP) are fabricated using the sol-gel method, and their spectroscopic properties are investigated. The longest fluorescence lifetime of 0.96 ms is obtained in YAP2 and YAP3 glasses. The emission cross-section (emi) and emi × of Yb3+ in the YAP1 glass are 1.00 pm2 and 0.94 pm2·ms, respectively. Co-doping with Al and P decreases the hydroxyl group content in the glasses because of the reduction in non-bridging oxygen content. The lowest OH content in the YAP3 glass is 9.6 ppm..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 081601 (2012)
Enhancement of upconversion luminescence of YAlO3: Er3+ by Gd3+ doping
Zhenlong Li, Baoshu Wang, Licheng Xing, Shaolong Liu, Na Tan, Siguo Xiao, and Jianwen Ding
The upconversion luminescences of YAlO3:Er3+ phosphor co-doping with different Gd3+ concentrations are investigated under the excitation of 980- and 532-nm diode lasers. A near ultraviolet upconversion emission at 410 nm is observed in YAlO3 under 532-nm excitation. Moreover, the inactive Gd3+ ions can improve the upcoThe upconversion luminescences of YAlO3:Er3+ phosphor co-doping with different Gd3+ concentrations are investigated under the excitation of 980- and 532-nm diode lasers. A near ultraviolet upconversion emission at 410 nm is observed in YAlO3 under 532-nm excitation. Moreover, the inactive Gd3+ ions can improve the upconversion intensity efficiently in a certain range of concentration. Under 980-nm excitation, the visible upconversion emissions at 546 and 646 nm are enhanced by about 10 and 8 times at the Gd3+ concentration of 40%, respectively. The upconversion emission at 410 nm under 532-nm excitation is also enhanced by 7 times. The substitution of Gd3+ ions for Y3+ sites changes the local symmetry of Er3+, leading to the improvement of upconversion efficiency..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 081602 (2012)
Nonlinear Optics
Generation of 40-as few-cycle pulse through chirp manipulation
Masoud Mohebbi, and Saeed Batebi
We discuss theoretically how supercontinuum spectra produced from high-order harmonic generation processes in a synthesized same-color laser field is optimized by adjusting the chirp parameter of the controlling pulse. Furthermore, a 40-attosecond isolated pulse with an effective bandwidth of 121 orders is obtained froWe discuss theoretically how supercontinuum spectra produced from high-order harmonic generation processes in a synthesized same-color laser field is optimized by adjusting the chirp parameter of the controlling pulse. Furthermore, a 40-attosecond isolated pulse with an effective bandwidth of 121 orders is obtained from He+ ion when the chirp rate ratio of pulses has a small value. The numerical results show that the efficiency of single as pulse generation is enhanced, and the quantum paths are controlled successfully. Our simulation shows that the produced pulses with high signal-to-noise ratio are obtained straightforwardly without any phase compensation. These results are explained using the classical approach..
Chinese Optics Letters
- Publication Date: May. 16, 2012
- Vol. 10, Issue 8, 081901 (2012)
Optical Devices
Experimentally distinguishing electro-optic ef fects in silicon
Jingcheng Zhu, Zhanguo Chen, Xiuhuan Liu, Jinbo Mu, Yanjun Gao, Wei Han, and Gang Jia
Different electro-optic effects, such as Kerr effect, Pockels effect induced by the electric field or strain, and plasma dispersion effect exist in silicon. Experimentally distinguishing these effects is necessary for designing silicon-based electro-optic devices. According to their different polarization dependencies Different electro-optic effects, such as Kerr effect, Pockels effect induced by the electric field or strain, and plasma dispersion effect exist in silicon. Experimentally distinguishing these effects is necessary for designing silicon-based electro-optic devices. According to their different polarization dependencies and frequency responses, these effects are measured and distinguished successfully via a transverse electro-optic modulation experiment based on the near-intrinsic silicon sample. The results indicate that Pockels effect induced by the electric field or strain is primary among these effects in the near-intrinsic silicon sample..
Chinese Optics Letters
- Publication Date: Jun. 15, 2012
- Vol. 10, Issue 8, 082301 (2012)
Quantum Optics
New approach for normalization and photon-number distributions of photon-added (-subtracted) squeezed thermal states
Liyun Hu, and Zhiming Zhang
Using the thermal field dynamics theory to convert the thermal state into a "pure" state in doubled Fock space, we find that the average value of e^{fa+a} under squeezed thermal state (STS) is just the generating function of Legendre polynomials. Based on this remarkable result, the normalization and photon-nUsing the thermal field dynamics theory to convert the thermal state into a "pure" state in doubled Fock space, we find that the average value of e^{fa+a} under squeezed thermal state (STS) is just the generating function of Legendre polynomials. Based on this remarkable result, the normalization and photon-number distributions of m-photon added (or subtracted) STSs are conviently obtained as the Legendre polynomials. This new concise method can be expanded to the entangled case..
Chinese Optics Letters
- Publication Date: May. 16, 2012
- Vol. 10, Issue 8, 082701 (2012)
Atomic and Molecular Physics
Laser cooling of rubidium 85 atoms in integrating sphere
Xucheng Wang, Huadong Cheng, Ling Xiao, Benchang Zheng, Yanling Meng, Liang Liu, and Yuzhu Wang
We cool 85Rb atoms in an integrating sphere directly from a vapor background using diffuse light generated by multiple reflections of laser beams in the inner surface of the integrating sphere. We compare and analyze the different features of cold 85Rb atoms and cold 87Rb atoms in diffuse light cooling, which are imporWe cool 85Rb atoms in an integrating sphere directly from a vapor background using diffuse light generated by multiple reflections of laser beams in the inner surface of the integrating sphere. We compare and analyze the different features of cold 85Rb atoms and cold 87Rb atoms in diffuse light cooling, which are important in applying 85Rb and 87Rb isotopes in many experiments on testing fundamental physics..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 080201 (2012)
Geometric Optics
Ray transfer matrix perturbation for an optical component with aberration
Jerry T., Clark Kendrick, and Stein Alec
The perturbation theory of matrices is applied to ray transfer matrices (RTMs) to describe an optical component with aberration. A quantitative description of the perturbation extent corresponding to aberration strength is provided using condition numbers and absolute errors for the perturbed RTM. An application to a sThe perturbation theory of matrices is applied to ray transfer matrices (RTMs) to describe an optical component with aberration. A quantitative description of the perturbation extent corresponding to aberration strength is provided using condition numbers and absolute errors for the perturbed RTM. An application to a single small aberration is presented, and the results are compared with those of the diffraction theory of aberrations..
Chinese Optics Letters
- Publication Date: May. 16, 2012
- Vol. 10, Issue 8, 080801 (2012)
Instrumentation, Measurement, and Metrology
Astigmatism-corrected miniature czerny-turner spectrometer with freeform cylindrical lens
Guo Xia, Bixiang Qu, Peng Liu, and Feihong Yu
A miniature, broadband, astigmatism-corrected Czerny-Turner spectrometer is proposed. Theories of the broadband astigmatism correction using freeform cylindrical lens are thoroughly analyzed. Comparisons of the freeform cylindrical lens method with those of titling cylindrical lens or wedge cylindrical lens methods areA miniature, broadband, astigmatism-corrected Czerny-Turner spectrometer is proposed. Theories of the broadband astigmatism correction using freeform cylindrical lens are thoroughly analyzed. Comparisons of the freeform cylindrical lens method with those of titling cylindrical lens or wedge cylindrical lens methods are also described. Results show the better spectrometer performance with the new optical design over a broadband spectral range from 300 to 800 nm..
Chinese Optics Letters
- Publication Date: Jun. 15, 2012
- Vol. 10, Issue 8, 081201 (2012)
Scattering
Random lasing in strongly disordered medium
Ke Yao, Guoying Feng, Liling Yang, Jiayu Yi, Yingsong Song, and Shouhuan Zhou
Using the time-dependent theory, we calculate the random-laser emission spectra in a two-dimensional strongly disordered medium. The calculation results show that in low dimensional systems, such as thinfilm disordered media and planar waveguides, the larger the difference of the refractive indices between the scatteriUsing the time-dependent theory, we calculate the random-laser emission spectra in a two-dimensional strongly disordered medium. The calculation results show that in low dimensional systems, such as thinfilm disordered media and planar waveguides, the larger the difference of the refractive indices between the scattering and background media, the smaller the lasing threshold. We also reveal the existence of multimode survival and mode competition. We experimentally obtain the emission spectra of a dye solution with Al particles doped at different pumping energies, and the experimental results agree well with the calculated ones..
Chinese Optics Letters
- Publication Date: May. 16, 2012
- Vol. 10, Issue 8, 082901 (2012)
Spectroscopy
Raman spectroscopy study of in situ change in laser irradiated LiMn2O4
Zhaojun Liu, Ligang Han, and Yujun Mo
A spinel LiMn2O4 is investigated via Raman spectroscopy at 514.5-nm excitation and X-ray diffraction. The dependence of Raman spectra on the different irradiated laser powers is determined and found to be different from that at 632.8-nm excitation. Based on our extensive analysis, our experimental results can be attribA spinel LiMn2O4 is investigated via Raman spectroscopy at 514.5-nm excitation and X-ray diffraction. The dependence of Raman spectra on the different irradiated laser powers is determined and found to be different from that at 632.8-nm excitation. Based on our extensive analysis, our experimental results can be attributed to the laser heating effect, which reduces the Mn4+ cation concentration in the local area. Consequently, the decrease in average Mn valence in the local area unavoidably induces the Jahn-Teller effect and local lattice distortion, which accounts for the evolution of the measured Raman spectra of spinel LiMn2O4..
Chinese Optics Letters
- Publication Date: May. 16, 2012
- Vol. 10, Issue 8, 083001 (2012)
Net analyte signal with floating reference theory in non-invasive blood glucose sensing by near-infrared spectroscopy
Wanjie Zhang, Rong Liu, Wen Zhang, Jiaxiang Zheng, and Kexin Xu
Based on the floating reference theory, a new method for extracting the net analyte signal (NAS) is proposed. The noise background subspace is spanned by spectra at the floating radial reference point, and then, the spectra at the measurement point are projected on the subspace. Thereafter, the glucose concentrations iBased on the floating reference theory, a new method for extracting the net analyte signal (NAS) is proposed. The noise background subspace is spanned by spectra at the floating radial reference point, and then, the spectra at the measurement point are projected on the subspace. Thereafter, the glucose concentrations in intralipid solutions are investigated through Monte Carlo simulation and experiments, and the partial least squares (PLS) models with and without NAS analysis are built. The root mean square errors of calibration and prediction reach to 28.87% and 27.33%, respectively. The results confirm the existence of information induced by glucose concentration variations as well as the validity of the floating reference theory..
Chinese Optics Letters
- Publication Date: Jun. 15, 2012
- Vol. 10, Issue 8, 083002 (2012)
Vision, Color, and Visual Optics
Investigation of Chinese skin colour and appearance for skin colour reproduction
Kaida Xiao, Ningfang Liao, Faraedon Zardawi, Haoxue Liu, Richard Van, Zhixiong Yang, Min Huang, and Julian M
A Chinese skin colour database is established based on measurements taken from nine bodies areas of 202 Chinese individuals to move towards accurate skin colour reproduction. The colour appearance of each skin point is predicted, and a comprehensive colour gamut for Chinese skin is determined. A consistent colour shiftA Chinese skin colour database is established based on measurements taken from nine bodies areas of 202 Chinese individuals to move towards accurate skin colour reproduction. The colour appearance of each skin point is predicted, and a comprehensive colour gamut for Chinese skin is determined. A consistent colour shift between facial and arm colours is identified, in which facial colour tends to be more reddish, more colourful, and darker than arm colour. Moreover, Chinese females are found to have lighter, paler, and more yellowish skin than Chinese males. Variations in Chinese skin colour are quantified, and body area differences and gender differences are shown to have significant effects on Chinese skin colour..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 083301 (2012)
Integrate Optics
Research on the thermo-characteristics of surface plasmon resonance spectrum
Yingcai Wu, and Zhengtian Gu
Based on the configuration of surface plasmon resonance (SPR) sensor, the SPR sensor model is set up, and the thermo-properties of various parts in the model are discussed. The thermo-characteristics of SPR spectra in wavelength interrogation and angular interrogation are investigated. Results show that thermo-optic anBased on the configuration of surface plasmon resonance (SPR) sensor, the SPR sensor model is set up, and the thermo-properties of various parts in the model are discussed. The thermo-characteristics of SPR spectra in wavelength interrogation and angular interrogation are investigated. Results show that thermo-optic and dispersion effects in the model deteriorate the sensitivity of SPR sensor, especially the thermo-optic effects. Mathematical expression is established to describe the resonance wavelength or angle, which is dependent of temperature. It demonstrates that the thermo-property of sensing medium excites the fluctuation of resonance wavelength or angle more intensely than that of the substrate or metal film in 1–2 orders. Our theoretical research is consistent with the previous experimental results..
Chinese Optics Letters
- Publication Date: Apr. 20, 2012
- Vol. 10, Issue 8, 081301 (2012)
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