Journals >Chinese Journal of Lasers
Contents
2012
Volume: 39 Issue 10
41 Article(s)
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[in Chinese]
Dual-Electron CO2 Model and Its High-Order Harmonic Generation Simulation
Fu Ning, Yu Chuan, Dai Chunyan, Zhang Guizhong, and Yao Jianquan
One-dimensional dual-electron model for CO2 is suggested on the basis of the electron configuration. Time-dependent Schrdinger equation is numerically solved by deploying symmetric split-operator technique for high-order harmonic generation (HHG) spectra of the CO2 model that is exposed to 800 nm wavelength laser pulsOne-dimensional dual-electron model for CO2 is suggested on the basis of the electron configuration. Time-dependent Schrdinger equation is numerically solved by deploying symmetric split-operator technique for high-order harmonic generation (HHG) spectra of the CO2 model that is exposed to 800 nm wavelength laser pulses. The computed results show that the present model for CO2 is moderate for computational load, and is able to elucidate the HHG characteristics. Laser pulse parameters play an important role in HHG, and the multi-cation nature of molecule may be responsible for the destructive interference in HHG spectra..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1017001 (2012)
[in Chinese]
Fine Tracking Mirror in Satellite-Based Quantum Key Distribution Based on Magneto-Optical Crystal and Two Mirrors
Zhao Guhao, Zhao Shanghong, Yao Zhoushi, Meng Wen, Wang Xiang, Zhu Zhihang, and Liu Feng
An optical polarization independence reflection structure applies to fine tracking mirror in satellite-based quantum key distribution is proposed. This structure is composed of magneto-optical crystal and two same mirrors. The results of simulation show that single mirror badly influences the polarization state. For thAn optical polarization independence reflection structure applies to fine tracking mirror in satellite-based quantum key distribution is proposed. This structure is composed of magneto-optical crystal and two same mirrors. The results of simulation show that single mirror badly influences the polarization state. For the mirror with refractive index 1.52, the quantum bit error rate caused by mirror is 40%. The quantum bit error rate caused by polarization independence reflection structure is not more than 0.25%, particularly, it is approaching zero when the deflection is approaching zero..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1018001 (2012)
Research Article
Wander and Spreading of Polarized and Partially Coherent Laser Propagation on Slant Path in Turbulence Atmospheric
Liu Jun, Wu Pengli, and Gao Ming
Wander and spreading of polarized and partially coherent laser propagation on slant path in turbulence atmospheric are studied by using the first and second moment of optical field as evaluation parameters. According to extended Huygens-Fresnel principle, the elliptically polarized and partially coherent laser beam is Wander and spreading of polarized and partially coherent laser propagation on slant path in turbulence atmospheric are studied by using the first and second moment of optical field as evaluation parameters. According to extended Huygens-Fresnel principle, the elliptically polarized and partially coherent laser beam is taken as a study object. The analytical expressions for barycentric coordinate, spreading radius and spreading angle of beam on the slant path are derived, and the effects of the phase difference between two orthogonal components of polarization beam, direction angle, wavelength, initial waist radius and receiver height on wander and spreading of laser beam are analyzed. Results show that the wander effect increases at first, and then decreases with the phase difference between two orthogonal components of polarization beam increasing under the certain slant path transmission distance and receiver height. The effect of wander and spreading of beam decreases with the increase of receiver height under the certain slant path transmission distance..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1013001 (2012)
Statistical Properties of Phase Noise Based on Stochastic Differential
He Jingbo, Hu Shengliang, Luo Yasong, and Liu Zhong
According to the intrinsic relations between the stochastic differential and the phase noise signal processing, the phase noise is systematically analyzed. The Fokker-Planck equation of phase noise is presented. The solution is given by using the Motion-Group Fourier transform equation. The joint probability density fuAccording to the intrinsic relations between the stochastic differential and the phase noise signal processing, the phase noise is systematically analyzed. The Fokker-Planck equation of phase noise is presented. The solution is given by using the Motion-Group Fourier transform equation. The joint probability density function of phase noise in the filter is given..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1017002 (2012)
Biomedical Photonics and Laser Medicine
Property of Light Propagation in Columnar Biological Tissue
Sun Meixiu, Zhang Liyun, Kang Meiling, Jiang Chenyu, and Zhang Chunping
The number density of photons absorbed in semi-infinite plane, simple columnar and double columnar biological tissues is numerically studied with Monte-Carlo method, respectively. The same optical parameters are used in the simulation for the three situations. The results show that the boundary employed in the simulatiThe number density of photons absorbed in semi-infinite plane, simple columnar and double columnar biological tissues is numerically studied with Monte-Carlo method, respectively. The same optical parameters are used in the simulation for the three situations. The results show that the boundary employed in the simulation has important effect on the light propagation in tissue. The effect of boundary on light propagation in tissue is investigated. Energy flow rate in biological tissue as a function of radial distance is simulated and the results agree well with experimental results..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1004001 (2012)
Orthogonal Polarization Filtering Image Enhancement Technology for Fluorescence Microscope
Wen Qiao, Wang Kaige, Shao Yonghong, Qu Junle, and Niu Hanben
In fluorescence microscope, the weak fluorescence signals are usually submerged in the strong excitation light. The fluorescence microscope image quality seriously depends on the ability to extract the faint fluorescence signal from the strong excitation light. At present, the image enhancement using frequency filterinIn fluorescence microscope, the weak fluorescence signals are usually submerged in the strong excitation light. The fluorescence microscope image quality seriously depends on the ability to extract the faint fluorescence signal from the strong excitation light. At present, the image enhancement using frequency filtering to filter out the excitation light, is often used in the fluorescence microscope, based on the differences between fluorescence and excitation wavelength. However, while this method is used, the parameters of the filter will be required highly, and seriously depend on the wavelength of the fluorescence and the excitation light. A polarization filtering image enhancement technology to filter out the excitation light and enhance image quality, is proposed, based on the differences of the polarization characteristic between the fluorescence and the excitation light. The experimental results indicate that when the filtering method is utilized, the image quality is improved significantly, and the requirements of the optical components performance parameters, is significantly reduced. The study is not only to enrich the technological method to extract the weak fluorescence signal from the strong excitation light, but also a reference for developing a light wavelength tunable multi-spectral fluorescence microscope..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1004002 (2012)
Holography and Information Processing
Weighted 3D GS algorithm for image-quality improvement of multi-plane holographic display
Fang Li, Yong Bi, Hao Wang, Minyuan Sun, and and Xinxin
Theoretically, three-dimensional (3D) GS algorithm can realize 3D displays; however, correlation of the output image is restricted because of the interaction among multiple planes, thus failing to meet the image-quality requirements in practical applications. We introduce the weight factors and propose the weighted 3D Theoretically, three-dimensional (3D) GS algorithm can realize 3D displays; however, correlation of the output image is restricted because of the interaction among multiple planes, thus failing to meet the image-quality requirements in practical applications. We introduce the weight factors and propose the weighted 3D GS algorithm, which can realize selective control of the correlation of multi-plane display based on the traditional 3D GS algorithm. Improvement in image quality is accomplished by the selection of appropriate weight factors..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1009001 (2012)
Improved Phase Unwrapping Algorithm Based on Image Segmentation and Mergers
Wang Huaying, Zhang Zhihui, Liu Feifei, Song Xiufa, Xiong Nanyan, Zhao Baoqun, Yu Mengjie, and Liu Zuoqiang
In order to increase the accuracy of the phase unwrapping algorithm based on image segmentation and merging, an improved algorithm based on existing algorithm is proposed. The method of unequal region segmentation is taken to make the regional information complete and accurate reproduction. For different regions with nIn order to increase the accuracy of the phase unwrapping algorithm based on image segmentation and merging, an improved algorithm based on existing algorithm is proposed. The method of unequal region segmentation is taken to make the regional information complete and accurate reproduction. For different regions with noise and under sampling conditions, different phase unwrapping algorithms are taken respectively. A weighted stack approach to improve the accuracy of the phase unwrapping results of merging the overlapping region of the block is presented. Simulation and measurement are taken to test the improved algorithm. The results show that the improved algorithm recovers the phase information of the measured object more accurately and faster. It is not only suitable for dealing with the phase unwrapping of large interferogram, but also for dealing with the wrapped phase which has areas with too dense stripes..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1009002 (2012)
Laser Devices and Laser Physics
[in Chinese]
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1017002 (2012)
Laser Manufacturing
Simulation and Experimental Study on Residual Stress Field of 2024 Aluminum Alloy Induced by Flat-Top Laser Beam
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and Charles LOY
Finite element simulation and experimental study on residual stress distribution of the 2024 aluminum alloy induced by flat-top laser shock are reported. Pressure distribution model of shock wave induced by flat-top laser beam is improved and applied to finite element simulation of residual stress field. High-quality fFinite element simulation and experimental study on residual stress distribution of the 2024 aluminum alloy induced by flat-top laser shock are reported. Pressure distribution model of shock wave induced by flat-top laser beam is improved and applied to finite element simulation of residual stress field. High-quality flat-top laser beams, which are suitable for laser shock processing (LSP), are aquired and used for experiments of laser shock processing of 2024 aluminum alloy. The experimental results are consistent with the simulation results. The results show that the characteristics of flat-top laser beam shock processing of 2024 aluminum alloy can be concluded as follows. Residual stress distribution is almost even in the surface of impacted area of 2024 aluminum alloy when shock wave pressure is below a certain level; and once it exceeds this level, shock wave will produce residual stress hole, however, the distribution style is nearly equal. The results in the depth direction indicate that the impacted depth and the depth of maximum residual stress increase with laser shock pressure increasing..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1003001 (2012)
Effect of Scanning Methods on the Cracking of the DZ125L Superalloy in Laser Direct Metal Forming
Doan Tatkhoa, Li Dichen, Lu Bingheng, Zhang Anfeng, He Bin, and Do Xuantuoi
The effect of scanning methods on stress distribution and cracking of the DZ125L superalloy thin-wall structures is investigated numerically and experimentally. The results demonstrat that the stress distribution is not uniform in single-direction scanning method, which leads to warping in both sides of the structures The effect of scanning methods on stress distribution and cracking of the DZ125L superalloy thin-wall structures is investigated numerically and experimentally. The results demonstrat that the stress distribution is not uniform in single-direction scanning method, which leads to warping in both sides of the structures and cracking in the middle regions. However, in back-and-forth scanning method, the stress distribution is relatively uniform, and the fabricated parts have smooth surface without any warping or cracking..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1003002 (2012)
Dissimilar Metals Combination of Superalloy/Stainless Steel in T-Shape by Laser Penetration Welding
Feng Weiqi, Zhang Yunfeng, Tao Wang, and Li Liqun
GH3128 and 06Cr19Ni10 which are mainly used in water wall of flight vehicle engine are joined together by laser penetration welding. The relationships between welding parameters and welding appearance and cracks are mainly researched. The reason of weld cracks is analyzed. A appropriate welding craft is summarized. TheGH3128 and 06Cr19Ni10 which are mainly used in water wall of flight vehicle engine are joined together by laser penetration welding. The relationships between welding parameters and welding appearance and cracks are mainly researched. The reason of weld cracks is analyzed. A appropriate welding craft is summarized. The following conclusions are obtained. The continuous laser welding is better than pulse laser welding in terms of welding appearance and welding process stability. If the gap between the two metals is too big, the surface of the welding seam will collapse. The GH3128 plate may crack if the laser power is too high, or if the laser beam deviate from the centre. The welded specimen which contains 41 weld seams preform well at the hydrostatic test (10 MPa, 5 min)..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1003003 (2012)
CO2 Laser Heating Fusion Welding Technique of Ultra-Thin Fused Silica Glass
Wang Wenhua, Yu Qingxu, and Jiang Xinsheng
The study on the heating fusion welding between the ultra-thin fused silica glass with 25 μm-thickness and the end face of the fused silica capillary tube is carried by using low power CO2 pulse laser with a pulse frequency of 40 kHz. The duty ratio, the defocus laser preheating and the defocus laser annealing impactinThe study on the heating fusion welding between the ultra-thin fused silica glass with 25 μm-thickness and the end face of the fused silica capillary tube is carried by using low power CO2 pulse laser with a pulse frequency of 40 kHz. The duty ratio, the defocus laser preheating and the defocus laser annealing impacting on the heating fusion welding of the fused silica glass are researched and analyzed. The results show that a duty ratio of 37% can perform perfectly the no penetration, sealing and firm welding between the ultra-thin fused silica glass and the fused silica capillary tube. For the welding without crack or split of the ultra-thin fused silica glass, the preheating of the +2 mm defocus pulse laser with a duty ratio of 20% plays a key role. The annealing of the -2 mm defocus pulse laser with an appropriate duty ratio can release the residual thermal stress produced in the process of the heating fusion welding in the ultra-thin fused silica glass, enhancing the performance of the fused silica device. The pressure and temperature linearity of the fiber-optic Fabry-Pérot sensor welded perfectly by the CO2 laser are 0.9995 and 0.9991, respectively, and their repeatabilities are good..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1003004 (2012)
Inlet/Outlet Arrangement Effect on the Flow Distribution and Heat Transfer in Mini-Channels
Liu Dong, Jiang Bin, and Liu Minghou
Different inlet/outlet arrangements are proposed for parallel mini-channels and their effects on the flow distribution and heat transfer are numerically studied. It is found that different arrangements have great impact on the characteristics of flow distribution. The velocity and surface temperature inequalization coeDifferent inlet/outlet arrangements are proposed for parallel mini-channels and their effects on the flow distribution and heat transfer are numerically studied. It is found that different arrangements have great impact on the characteristics of flow distribution. The velocity and surface temperature inequalization coefficient are introduced to evaluate the effects of inlet/outlet arrangements. The results show that the velocity inequalization coefficient increases with the rise of flow flux when the inlet/outlet arrangement is fixed. The velocity inequalization coefficient of upper center (UC)-type arrangement is minimum in these numerical cases. And when the channel area is fixed, the velocity inequalization coefficient decreases with the rise of channel numbers. The surface temperature inequalization coefficient increases with the heat power. When the heat flux is fixed, the heat resistance decreases with the rise of heat flux and finally trends to a constant..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1003005 (2012)
Effect of Tempering on Microstructure and Wear Resistance of Laser Cladding Ni-Base Reinforced Particles Composite Coating
Wang Chuanqi, Liu Hongxi, Zhou Rong, Jiang Yehua, and Zhang Xiaowei
The particles reinforced multi-pass Ni60CuMoW composite coatings are fabricated by optimizing laser cladding process on the surface of 45# steel. The microstructure, particles phase distribution and structure features are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersThe particles reinforced multi-pass Ni60CuMoW composite coatings are fabricated by optimizing laser cladding process on the surface of 45# steel. The microstructure, particles phase distribution and structure features are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS). The micro hardness distribution and wear resistance of heat treatment composite coatings are measured by microscopic hardness tester and disc-pin dry friction and wear apparatus. The influence of heat treatment on wear mechanism is analyzed. The results show that the precipitation composite carbide and boride after tempering treatment have a good metallurgical bonding with 45# steel substrate in the range of 0.3~0.8 mm from interface. The composite coatings has the characteristics of integrality dimension distribution uniformry and high density. Compared with the 45# steel matrix, the average microhardness of the laser cladding Ni60CuMoW composite coatings before and after heat treatment increases by 4.9 times and 5.8 times, and the wear resistance increases by 1.1 times and 2.9 times, respectively..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1003006 (2012)
Laser Physics
Study of Thermal Deformations Induced Optical Aberrations for Al2O3 Mirror in an Optical System
Zhou Qiong, Jiang Zongfu, and Xi Fengjie
Based on the finite element method (FEM) and Zernike polynomial, the thermal deformation aberrations of Al2O3 mirror in an optical system are calculated. The phase shifts of reflected laser beam and transmitted beacon beam are theoretically analyzed, respectively. The defocusing is the major aberration of reflected lasBased on the finite element method (FEM) and Zernike polynomial, the thermal deformation aberrations of Al2O3 mirror in an optical system are calculated. The phase shifts of reflected laser beam and transmitted beacon beam are theoretically analyzed, respectively. The defocusing is the major aberration of reflected laser beam and the defocusing and the primary spherical aberrations are the major aberrations of transmitted beacon beam. The primary spherical aberration is induced by the uneven temperature distribution at the boundary of laser irradiation area. The aberration ratio γnm is defined to describe the influence of absorption power on aberration of reflected laser beam and transmitted beacon beam. The defocusing ratio of reflected laser beam γ20 is 0.0393, and the defocusing ratio of transmitted beacon beam γ20 is -0.0011 and the primary spherical ratio γ40 is -0.0033..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1002001 (2012)
Wavelength Selectable DFB Laser Based on Non-Uniform Multiple Quantum Wells
Xie Hongyun, uo Wenjuan, Jiang Zhiyun, Lu Zhiyi, and Zhang Wanrong
A monolithic integrated chip with DFB lasers in serial is presented, which provides two selectable wavelengths for coarse wave divide multiplexing (CWDM) channel at suitable working condition. Non-uniform multiple quantum wells is designed and grown to widen active material gain spectrum. Weak gain coupled is added intA monolithic integrated chip with DFB lasers in serial is presented, which provides two selectable wavelengths for coarse wave divide multiplexing (CWDM) channel at suitable working condition. Non-uniform multiple quantum wells is designed and grown to widen active material gain spectrum. Weak gain coupled is added into pure refractive index grating of each DFB laser to promote dynamic single mode. The monolithic chip is fabricated with common process of DFB laser, which has the features of simple process, low cost and high repetition. Test results show that the chip can output at two wavelengths of 1.51 μm and 1.53 μm. Output powers are both higher than 6 mW and single mode suppression ratios both achieve 40 dB..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1002002 (2012)
Analysis of the Thermal Model Based on the Carrier Injection Mechanisms within the Semiconductor Laser
Zhang Jianwei, Ning Yongqiang, Zhang Xing, Zhang Jian, Liu Yun, Qin Li, and Wang Lijun
In order to solve the problems existed in the calculation of self heating in the active layer of semiconductor lasers, a new model for simulating the self-heating is introduced. The heat source induced by the carrier injection is analyzed. And the method for calculating the conductance of hetero-junction is also investIn order to solve the problems existed in the calculation of self heating in the active layer of semiconductor lasers, a new model for simulating the self-heating is introduced. The heat source induced by the carrier injection is analyzed. And the method for calculating the conductance of hetero-junction is also investigated to improve the precision of calculated joule heat. Edge emitting laser is fabricated, and the width of P-contact and stripe of fabricated laser are 10 μm and 20 μm, respectively. From the simulation result, the heat source density deduced from the traditional experience model is much lower than that from the optimized thermal model suggested. Thus a lower temperature rising is proposed in the experience model. By testing the shift of the lasing characteristics at different injected currents, the temperature of active layer is gained. Finally, the change of temperature with injected current obtained from simulation and testing is compared. The temperature rising gained from the experience model is lower than that of the experimental one. However, the new optimized model solves this problem. As a result of the optimized model, the maximum deviation between simulated temperature rising and tested one is about 0.2 K when the injected current is above the threshold current..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1002003 (2012)
Suppressing Amplified Spontaneous Emission in High-Power Pulsed Er-Yb Codoped Fiber Amplifiers
He Yang, Han Qun, Ning Jiping, Sheng Zhaoxia, and Ren Kun
In order to investigate the impact of the amplified spontaneous emission (ASE) on the performance of high-power pulsed Er-Yb codoped fiber amplifiers (EYDFAs), several EYDFAs with different input signal parameters are studied numerically. The results show that the Yb-band (1.0~1.1 μm) ASE is the main factor that limitsIn order to investigate the impact of the amplified spontaneous emission (ASE) on the performance of high-power pulsed Er-Yb codoped fiber amplifiers (EYDFAs), several EYDFAs with different input signal parameters are studied numerically. The results show that the Yb-band (1.0~1.1 μm) ASE is the main factor that limits the efficiency of a high-power pumped EYDFA. Therefore, suppressing the Yb-band ASE can effectively help to improve the performance of the amplifiers. It is found that adding an Yb-band signal at the pump end can help to reduce the Yb-band ASE effectively. Simultaneously, this method can also enhance the power conversion efficiency and improve the output power of the amplifiers..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1002004 (2012)
Materials and Thin Films
Characteristics of Photonic-Crystal Waveguides with Random Media
Li Xin, Yang Ming, Guo Shiliang, and Li Zhiquan
A special type of waveguides consisting of photonic crystal waveguide and random media is investigated. Based on the photonic crystal waveguide model, a new kind of photonic crystal waveguides with random media is put forward. In this paper, by employing the finite-difference time-domain (FDTD) method, the influences oA special type of waveguides consisting of photonic crystal waveguide and random media is investigated. Based on the photonic crystal waveguide model, a new kind of photonic crystal waveguides with random media is put forward. In this paper, by employing the finite-difference time-domain (FDTD) method, the influences of the embedded ZnO random particles on the frequency, time-domain, gain characteristics of photonic crystal waveguide are studied. The simulation results demonstrate that in the present of random media in the defect layer of photonic crystal, the light in the defect area is obviously amplified, and the localization level is higher than the pure random media and photonic crystal waveguide, respectively. In addition, the interaction time between the random gain medium and the light is lengthened and the threshold is reduced. The waveguide can be used in the field of integrated optical system and microlaser with low threshold..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1006001 (2012)
Mid-Infrared Luminescence and Energy Transfer Mechanism of Tm3+/Ho3+ Co-Doped Tellurite Glasses
Xu Xingchen, Zhou Yaxun, Dai Shixun, Wang Xunsi, Zheng Shichao, and Yin Dandan
Tm3+/Ho3+ co-doped tellurite glasses with the composition of TeO2-ZnO-Na2O are prepared by the high temperature melt-quenching method. The intensity parameters Ωt(t=2,4,6), spontaneous radiative transition rates A, fluorescence branching ratios β and radiation lifetimes τrad of Ho3+ are calculated from the measured absTm3+/Ho3+ co-doped tellurite glasses with the composition of TeO2-ZnO-Na2O are prepared by the high temperature melt-quenching method. The intensity parameters Ωt(t=2,4,6), spontaneous radiative transition rates A, fluorescence branching ratios β and radiation lifetimes τrad of Ho3+ are calculated from the measured absorption spectra with the Judd-Ofelt theory. Meanwhile, the fluorescence spectra of glass samples with different doped concentration of Ho3+ ions are measured, and the results show the intense mid-infrared fluorescence emission around 2.0 μm band in the Tm3+/Ho3+ co-doped tellurite glasses pumped by 808 nm diode laser. The analysis indicates that the mid-infrared emission of Ho3+ ions is mainly the result of resonant energy transfer from Tm3+ to Tm3+ ions, and then zero phonon- and one phonon-assisted nonresonant energy transfer from Tm3+ to Ho3+ ions. The energy transfer micro-rates, critical radius and phonon contributions for the above energy transfer process are calculated and analyzed. Meanwhile, the absorption, stimulated emission cross-sections and gain coefficient of Ho3+5I7→5I8 transitions are calculated. The research shows that Tm3+/Ho3+ co-doped TeO2-ZnO-Na2O glass is a promising host material applied for 2.0 μm-band mid-infrared solid laser..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1006002 (2012)
Laser Induced Voltage Effect of (Bi,Pb)2Sr2CaCu2O8 Thin Films
Zhang Hui, He Enquan, and Yang Ning
Pulsed laser deposition technique is employed to grow c axis oriented (Bi,Pb)2Sr2CaCu2O8[(Bi,Pb)-2212]/LaAlO3(100) thin films under both the low and high temperature deposition process. The laser induced thermoelectric voltage (LITV) effect is studied on the films grown on vicinal-cut LaAlO3(100) substrates; the influePulsed laser deposition technique is employed to grow c axis oriented (Bi,Pb)2Sr2CaCu2O8[(Bi,Pb)-2212]/LaAlO3(100) thin films under both the low and high temperature deposition process. The laser induced thermoelectric voltage (LITV) effect is studied on the films grown on vicinal-cut LaAlO3(100) substrates; the influences of deposition time and incident laser energy on LITV signals are investigated. Moreover, in order to prevent laser-ablating or laser-evaperating of the films, (Bi,Pb)-2212 film coated with MgO layer is prepared, and the effect of MgO protecting layer on LITV signals of the films is studied. The result shows that LITV effect can be dramatically enhanced by MgO protection layer..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1007001 (2012)
Optical Characterization and Structure Properties of Ultraviolet LaF3 Thin Films by Thermal Evaporation
Chang Yanhe, Jin Chunshui, Li Chun, and Jin Jingcheng
LaF3 single layers are prepared by thermal evaporation at different deposition temperatures on JGS1. Refractive index and extinction coefficient are obtained from the measured transmittance and reflectance spectral curve. Atomic force microscopy (AFM) is used to measure the surface morphology and roughness. The crystalLaF3 single layers are prepared by thermal evaporation at different deposition temperatures on JGS1. Refractive index and extinction coefficient are obtained from the measured transmittance and reflectance spectral curve. Atomic force microscopy (AFM) is used to measure the surface morphology and roughness. The crystal structures and grain size of the thin films are evaluated by X-ray diffraction (XRD). It is found that the crystallization status becomes more compact and the refractive index increases with the deposited temperature. The optical constants and refractive index inhomogeneity of the thin films present linearity. The increasing total optical loss with deposited temperature is attributed to the absorption because the scattering occupies a very low percent in the whole loss..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1007002 (2012)
Measurement and Metrology
Wavefront Error Testing of Off-Axis Three-Mirror Anastigmatic System Using Phase Diversity Technology
Cheng Qiang, Yan Feng, Xue Donglin, Zheng Ligong, and Zhang Xuejun
The basic principles of wavefront sensing based on phase diversity (PD) technology are expatiated, and the genetic algorithm (GA) is proposed to be applied in the data post-processing of PD testing aiming at dealing with the multi variables and the highly nonlinearity of merit function. The wavefront error of an off-axThe basic principles of wavefront sensing based on phase diversity (PD) technology are expatiated, and the genetic algorithm (GA) is proposed to be applied in the data post-processing of PD testing aiming at dealing with the multi variables and the highly nonlinearity of merit function. The wavefront error of an off-axis three-mirror anastigmatic (TMA) system is tested with PD technology based on extended target, in which the defocused image is obtained by shifting the image plane. To verify the improvement of image quality and phase estimation of PD technology, a comparison experiment of extended object on high-resolution imaging and phase estimation is carried out based on the PD and interferometric testing. It can be observed that the deviation of root mean square (RMS) between the wavefront error obtained by PD testing and by interferometric testing is 0.0329λ (RMS) for the coarse-aligned off-axis TMA system, and the deviation decreases to 0.013λ (RMS) when the system is well aligned. The precision of PD technology can satisfy the requirement of engineering. The imaging experiments are also carried out and image quality can be well improved according to the wavefront estimated by PD..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1008001 (2012)
Development of Portable Multi-Optical Axes Parallelism Calibration System
Li Yacan, Qiu Lirong, Zhang Pengsong, Sha Dingguo, and Zhao Weiqian
To satisfy the need of field measurement of the multi-optical axes parallelism of photoelectronic equipments, a portable axes parallelism calibration system is developed. The collimation of Cassegrain optical system and ZnS reticle is used in the system to create infinite reticle object and to provide aiming baseline fTo satisfy the need of field measurement of the multi-optical axes parallelism of photoelectronic equipments, a portable axes parallelism calibration system is developed. The collimation of Cassegrain optical system and ZnS reticle is used in the system to create infinite reticle object and to provide aiming baseline for the original system and realising the parallelism calibration between television axis and infrared axis. A CCD system is adopted to collect crosswire on the reticle and laser facula on the target sheet. On the basis of the bias between the detected reticle centre and laser spot centre, parallelism calibration for laser axis and visible axis is achieved. An optical angle gauge is applied in this system to make calibration precision to approach angle second level. Experimental analytical results show that the standard uncertainty of this measurement for the parallelism between the TV-axis and the infrared-axis can reach 2″ and the standard uncertainty of this measurement for the parallelism between the sighting axis and the receiving axis of laser can reach 5″..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1008002 (2012)
Error Modeling and Compensating of Fiber Optic Gyro Based on Wavelet Analysis and Grey Neural Network
Tang Xiaqing, Cheng Xuwei, Guo Libing, Zhang Huan, and Wu Meng
In order to compensate the high frequency noises and drift errors of fiber optic gyro (FOG) in attitude measurement system under disturbing environment, a new drift error modeling method based on Ⅱ generation wavelet transform and grey neural network algorithm is proposed. The Allan variance method is adopted to analyzIn order to compensate the high frequency noises and drift errors of fiber optic gyro (FOG) in attitude measurement system under disturbing environment, a new drift error modeling method based on Ⅱ generation wavelet transform and grey neural network algorithm is proposed. The Allan variance method is adopted to analyze the output signal of FOG under disturbing circumstance. Ⅱ generation wavelet transform is applied to separate drift errors and high frequency white noises. After greying drift signal, an Elman neural network for modeling and compensation is established. Experimental results show that, compared to single grey theory model or Elman neural network, the proposed method eliminates white noise effectively, and improves modeling precision up to 96%, which increases the strike precision of combat vehicle..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1008003 (2012)
Projector Calibration Method Based on Projective Transformation for Structured Light Measurement System
Gao Zhihua, Wang Zhao, Huang Junhui, and Gao Jianmin
For structured light measurement system, parameter calibration is the key technique of measurement. However the accuracy of projector parameters calibration is low. A simple, convenient and accurate method is put forward, which is done by projecting circles pattern to a flat with circular signalized points. FundamentalFor structured light measurement system, parameter calibration is the key technique of measurement. However the accuracy of projector parameters calibration is low. A simple, convenient and accurate method is put forward, which is done by projecting circles pattern to a flat with circular signalized points. Fundamental corresponding relation is established between projector image and camera image based on projective transformation theory. After that accurate corresponding relation is established by using bivariate quartic function to fit and compensate error. It is obtained for the accurate projector image coordinates of circular signalized points on the flat. Then, projector calibration is accomplished. Simulation and experimental results demonstrate that the proposed method can get better precision, and experiments verify that the maximum value and efficient value of projector calibration error is less than 0.1 and 0.03 pixel respectively, and the system measurement precision is about 0.06 mm..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1008004 (2012)
Refractive Index of Liquid Measured by Liquid-Core Zoom Cylindrical Lens
Li Qiang, Sun Licun, Meng Weidong, and Pu Xiaoyun
A liquid-core-zoom cylindrical lens has been fabricated, which is used to measure accurately the refractive index of liquid filled into the core region of the cylindrical lens. The focal length of such a cylindrical lens varies with the refractive index of core liquid, which can be known by measuring experimentally theA liquid-core-zoom cylindrical lens has been fabricated, which is used to measure accurately the refractive index of liquid filled into the core region of the cylindrical lens. The focal length of such a cylindrical lens varies with the refractive index of core liquid, which can be known by measuring experimentally the related focal length. Due to a high sensitivity in measuring refractive index and a short depth of field, a high accuracy in measurement of refractive index is ensured. The accuracy of refractive index for one single measurement is better than 0.0002 in the range of 1.3~1.642, when a 20× objective is used in a reading microscope. By either enhancing sensitivity of refractive index of the cylindrical lens or enlarging effective numerical aperture of the measurement system, the accuracy of refractive index can be further improved..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1008005 (2012)
In-Situ Calibration Method for Large-Scale Space Angle Optical Measurement System
Hu Wenchuan, Qiu Zurong, and Zhang Guoxiong
In order to achieve the in-situ calibration of the measurement of angle between bifacial lines in large-scale space, the calibration approach based on target is proposed. A practical engineering project is taken to introduce the measuring principle, and in-situ calibration strategy which is suitable for quickly implemeIn order to achieve the in-situ calibration of the measurement of angle between bifacial lines in large-scale space, the calibration approach based on target is proposed. A practical engineering project is taken to introduce the measuring principle, and in-situ calibration strategy which is suitable for quickly implementation is presented. The error sources of measurement system are analyzed and the design proposal of system calibration board is proposed. The reasonableness of framework design and layout of calibration board is checked. The digital image processing algorithm of calibration is designed, and the result of each step is proposed. Experiments indicate that the mean error of the visual inspection system is reduced from 0.065123° to 0.00219° using the calibration method with the illumination condition of 355 lx. The effect of error compensation meets the requirement, and the standard uncertainty of measurement for the angle of bifacial lines separated at a distance of 7 m is 0.114°..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1008006 (2012)
Micro and Nano Optics
Propagation Properties of a Surface Plasmon Polariton Directional Coupler
Li Zhiquan, Gao Xiaoguang, Niu Liyong, and Zhang Xin
A kind of surface plasmon polariton (SPP) directional coupler in which metal strip between the two adjacent waveguides is thinner than the metal film is simulated by using three dimensional full-vectorial finite difference time-domain (FDTD) method. The distributions of electromagnetic field and longitudinal energy fluA kind of surface plasmon polariton (SPP) directional coupler in which metal strip between the two adjacent waveguides is thinner than the metal film is simulated by using three dimensional full-vectorial finite difference time-domain (FDTD) method. The distributions of electromagnetic field and longitudinal energy flux density when only fundamental mode propagates in waveguides are analysed, and the dependences of coupling length and maximum transfer power on the height of metal strip are discussed. Results show that the energy flux density along the propagation direction distributions mainly in the part near the metal strip, which is beneficial to increase the coupling strength. Also, the efficient decrease of coupling length in directional coupler can be achieved by reducing the height of metal strip between waveguides. This sub-wavelength of directional coupler can be applicable for the optical integrated circuit based on surface plasmon polaritons..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1010001 (2012)
Optical Communication
All Single-Mode Fiber Fabry-Pérot Interferometric High Temperature Sensor Fabricated with Femtosecond Laser
Wang Wenyuan, Wen Jianxiang, Pang Fufei, Chen Na, and Wang Tingyun
Fiber-optic intrinsic Fabry-Pérot interferometric (IFPI) sensor, fabricated in standard single-mode fiber with femtosecond (fs) laser, which can be used for high temperature measurements is proposed. The fiber-optic IFPI sensor consists of a pair of internal reflectors inscribed by the femtosecond laser and the inFiber-optic intrinsic Fabry-Pérot interferometric (IFPI) sensor, fabricated in standard single-mode fiber with femtosecond (fs) laser, which can be used for high temperature measurements is proposed. The fiber-optic IFPI sensor consists of a pair of internal reflectors inscribed by the femtosecond laser and the in-cavity fiber. The fringe contrast of the reflection spectrum of the sensor reaches 10 dB and the insert loss is only 0.1 dB. The experimental results show that the measurable temperature of this sensor is up to 1000 ℃ and the temperature sensitivity is 14.9 pm/℃. The repeatability of the reflection spectra is very high in many measurements, which indicates that the sensor can achieve accurate measurement of high temperature. The sensor is simple, low-cost and easy to connect to the existing fiber-optic devices, so it suits for fiber-optic sensing network and has a great value in engineering..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1005001 (2012)
Performance Analysis of Inter-High Altitude Platform Optical Links with Pointing Errors Modeled by Hoyt Distributions
Wang Xiang, Zhao Shanghong, Shi Lei, Li Yongjun, Zhao Guhao, Zhu Zihang, and Zhao Weihu
Based on the model of high altitude platforms (HAP) position instability, the factual Hoyt distribution model which is brought by optical pointing error is constructed. Compared with the ideal Rayleigh distribution model, performance of inter-platforms is analyzed. The simulation results show that there is a similar ruBased on the model of high altitude platforms (HAP) position instability, the factual Hoyt distribution model which is brought by optical pointing error is constructed. Compared with the ideal Rayleigh distribution model, performance of inter-platforms is analyzed. The simulation results show that there is a similar rule between the factual model and the ideal model with the increase of divergence angle. Under the condition of the same divergence angle, the bit error rate (BER) of Hoyt distribution model is lower than that of Rayleigh distribution model. When the divergence angle is optimized, the difference between factual and ideal distribution model is the biggest. Take 0.2 of root mean square (RMS) ratio as an example, compared with the Rayleigh distribution model, the BER of Hoyt distribution model reduces approximately by 9 dB..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1005002 (2012)
Fiber Bragg Grating Temperature Sensor Based on Dynamic Fabry-Pérot Cavity
Fan Liujing, Ma Li, Han Daofu, and He Shui
A method of demodulation wavelength with the dynamic extrinsic Fabry-Pérot (F-P) cavity is proposed. The reflected light of fiber Bragg grating (FBG) is modulated by the F-P cavity which is constructed of a piezoelectric ceramics (PZT). By the theoretical analysis, the modulated intensity varies with the length ofA method of demodulation wavelength with the dynamic extrinsic Fabry-Pérot (F-P) cavity is proposed. The reflected light of fiber Bragg grating (FBG) is modulated by the F-P cavity which is constructed of a piezoelectric ceramics (PZT). By the theoretical analysis, the modulated intensity varies with the length of F-P cavity as cosine-like. When PZT has a vibration driven by a sine voltage, the cosine-like signal moves, and a linear relationship between the signal curve shift and FBG wavelength offset is numerically simulated, which can be applied to FBG wavelength of demodulation. Utilizing a temperature measurement system made up of the F-P cavity and a FBG, the liquid temperature measurement is carried out at different temperatures. Linear relationship between variation of the liquid temperature and the displacement of cosine-like signal is proved when the temperature changes from 35 ℃ to 80 ℃, and the linear fitting degree reaches to 99.5%..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1005003 (2012)
Short Length Polarization Splitter Based on Dual Elliptical-Core Photonic Crystal Fiber
Li Rongmin, Cao Ye, and Tong Zhengrong
Based on the birefringence effect, a novel polarization splitter based on dual elliptical-core photonic crystal fiber (PCF) is proposed, the elliptical-core through introducing a pair of big air holes and a pair of small air holes in every core. The full-vector finite element method (FEM) and the semi-vector beam propaBased on the birefringence effect, a novel polarization splitter based on dual elliptical-core photonic crystal fiber (PCF) is proposed, the elliptical-core through introducing a pair of big air holes and a pair of small air holes in every core. The full-vector finite element method (FEM) and the semi-vector beam propagation method (BPM) are employed to analyze the performance of the splitter. Numerical simulations demonstrate that it is possible to obtain a 544 μm long polarization splitter, and the polarized light extinction ratio is -43.75 dB at the wavelength of 1.55 μm. Besides, the bandwith is over 80 nm when the extinction ratio is less than -10 dB. Such design provides a new approach to get highly extinction ratio and short length polarization splitter based on dual-core photonic crystal fiber..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1005004 (2012)
Suppression of Rayleigh Scattering Induced Coherent Noise in Remotely Interrogated Fiber-Optic Hydrophones
Cao Chunyan, Hu Zhengliang, Xiong Shuidong, and Hu Yongming
Rayleigh scattering induces serious coherent noise in remotely interrogated fiber-optic interferometric hydrophones especially when high coherence laser sources are used. The impacts of Rayleigh backscatter (RB) and double Rayleigh scattering (DRS) on hydrophone systems are analyzed and optical isolators are used to elRayleigh scattering induces serious coherent noise in remotely interrogated fiber-optic interferometric hydrophones especially when high coherence laser sources are used. The impacts of Rayleigh backscatter (RB) and double Rayleigh scattering (DRS) on hydrophone systems are analyzed and optical isolators are used to eliminate noise due to RB. Then the phase noise due to DRS and its characteristics are investigated, and it is inferred that phase generation carried (PGC) technique can suppress these coherent noises besides its general function of overcoming bias induced signal fading. In an experimental setup with 25 km input and output fibers, a maximal 20 dB decrease of phase noise is achieved by the use of isolators. A further decrease of maximal 10 dB is achieved by PGC technique. Thus when RB and DRS are suppressed simultaneously, Rayleigh scattering induced coherent noise in a 50 km system is almost eliminated..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1005005 (2012)
Chaotic-laser-based true random sequence generation for spread-spectrum communications
Zhaoxia Zhang, Junjie Zhou, Dongze Zhang, Zheng Fu, and and Jianzhong
We propose a scheme for spread-spectrum communications using true random sequences generated by chaotic semiconductor lasers as spreading codes. These sequences can eliminate the inherent periodicity of pseudorandom sequences, enlarge the capacity of spread-spectrum codes, improve communication security, and increase tWe propose a scheme for spread-spectrum communications using true random sequences generated by chaotic semiconductor lasers as spreading codes. These sequences can eliminate the inherent periodicity of pseudorandom sequences, enlarge the capacity of spread-spectrum codes, improve communication security, and increase the number of users of the system. When a true random sequence with an appropriate length is used as the spread-spectrum code and the information speed is maintained constant, the system acquires a greater spread-spectrum gain and a lower bit-error ratio (BER) than the traditional spread-spectrum system. The communication security is also enhanced. The BER smoothly increases with the number of users, which indicates the good multiple-access capability of the system..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1005006 (2012)
Optical Design and Fabrication
Design and Realization of Staring Laser Detecting and Warning System Based on Sinusoidal Grating
Zhang Chao, Niu Yanxiong, Su Ping, He Ting, Zhang Peng, Niu Haisha, and Li Yinan
Incident laser passing through sinusoidal grating diffracts as zero-order and plus or minus one-order spectra. The wavelength and direction of incident laser can be measured by reading the position of the spectrum from the detector. In order to detect the wavelength and direction of laser light, a staring laser detectiIncident laser passing through sinusoidal grating diffracts as zero-order and plus or minus one-order spectra. The wavelength and direction of incident laser can be measured by reading the position of the spectrum from the detector. In order to detect the wavelength and direction of laser light, a staring laser detecting and warning system based on sinusoidal grating is designed. Working principle of the system is introduced, computing formulas of wavelength and azimuth of the incident laser are deduced, and detecting accuracy is studied by numerical simulation. Influence of grating constant and cylindrical lens radius on detectivity of the system is studied and the related function is provided. Experimental results show that the laser detecting and warning system can realize real time measurement of laser with the wavelength range of 320~1100 nm, field of view of ±20° when the grating constant is 1/500 nm and the cylindrical lens radius is 20 mm, where the wavelength resolution is less than 10 nm and the angular resolution is less than 1°..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1016001 (2012)
Non-Sandwich-Structured Tunable Transverse Superresolving Pupil Filters Based on Birefringent Crystals
Zhu Huafeng, Liu Weisen, Heng Keyin, Chen Sheng, and Ge Lina
The optical properties of "non-sandwich-structured" zonal pupil filter based on birefringent crystal are studied in focusing optical systems with low numerical aperture. The exact pupil function of the new filter is presented by taking glass and birefringent crystal for the inner and outer zone respectively aThe optical properties of "non-sandwich-structured" zonal pupil filter based on birefringent crystal are studied in focusing optical systems with low numerical aperture. The exact pupil function of the new filter is presented by taking glass and birefringent crystal for the inner and outer zone respectively as an example. Numerical simulations of its optical properties are carried out with scalar diffraction theory, which shows that tunable transverse superresolution properties as well as extended axial focal depth can be obtained by rotating the pupil filter. This kind of filter has higher light utilization ratio than the existed pupil filters based on birefringent crystals, and its tunable ability can provide more flexibility in practical applications..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1016002 (2012)
Remote Sensing and Sensors
Laser Coherent Detection of Moving Target Based on Micro-Doppler Effect
Dong Jing, Chen Rui, Li Xiaolong, and Zhang Jun
A laser coherent detection system, operating at 1550 nm and all fiber designed, is set up and a large aperture lens of 200 mm is used to collect scattered light. Using this system, the micro-Doppler effect of moving target is detected. The results of the signal analysis in spectrum analysis and time-frequency analysis A laser coherent detection system, operating at 1550 nm and all fiber designed, is set up and a large aperture lens of 200 mm is used to collect scattered light. Using this system, the micro-Doppler effect of moving target is detected. The results of the signal analysis in spectrum analysis and time-frequency analysis show that time-frequency analysis is effectively to the feature extraction of micro-Doppler signal of moving target, which is time-varying. The different targets of 20~2000 Hz can be identified and classified by these characteristics. It provides an effective method of the feature extraction, classification and recognition of the target..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1014001 (2012)
Two-Wavelength Polarization Airborne Lidar for Observation of Aerosol and Cloud
Bo Guangyu, Liu Dong, Wang Bangxin, Wu Decheng, and Zhong Zhiqing
A two-wavelength polarization airborne lidar is designed for detecting three-dimensional distributions of aerosols and clouds and its interaction on both regional and global dimension. The design and operation of the lidar system are discussed. Simulation results of the lidar specifications are presented. Some key techA two-wavelength polarization airborne lidar is designed for detecting three-dimensional distributions of aerosols and clouds and its interaction on both regional and global dimension. The design and operation of the lidar system are discussed. Simulation results of the lidar specifications are presented. Some key techniques adopted in developing the airborne lidar are depicted. The ground experimental result suggests that the lidar system can achieve the detection performance as wanted. Initial result from airborne measurement shows that the airborne lidar meets the aviation applications on weight, size, power and operating environment restrictions. In the future, integrated atmospheric observations using lidar along with other passive remote sensing instrument aboard on the aircraft, will improve our understanding of atmospheric composition and environment element..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1014002 (2012)
Spectroscopy
Spatial Coding Modulation Effect of Compressive Spectral Imaging
Chen Yuheng, Chen Xinhua, Zhou Jiankang, Ji Yiqun, and Shen Weimin
The spatial light modulation process makes direct effort on imaging data fidelity of the spatial coding compressive spectral imaging. To expand existing coding patterns for spatial light modulation in compressive spectral imaging and reveal its relation it and the imaging data fidelity, the research on coding modulatioThe spatial light modulation process makes direct effort on imaging data fidelity of the spatial coding compressive spectral imaging. To expand existing coding patterns for spatial light modulation in compressive spectral imaging and reveal its relation it and the imaging data fidelity, the research on coding modulation effect in compressive spectral imaging is carried out. Based on the physical model of imaging system, present binaryzation coding amplitude modulation method is extended, the research on non-binaryzation continuous amplitude modulation is adopted and the phase modulation method is also verified. The root-mean-square error of the full-spectrum images is worked out so that the correlation between modulation coding pattern and the imaging data fidelity is quantitatively revealed. The simulation scenery of certain spatial and spectral features is constructed so that the imaging simulating experiment is carried out. The imaging results under six kinds of spatial coding modulation conditions are compared. The employing feasibility of non-binaryzation amplitude coding modulation is verified and the ralidity of data fidelity improved by the spatial light phase modulation is testified..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 10, 1015001 (2012)
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