Journals >Laser & Optoelectronics Progress
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2016
Volume: 53 Issue 9
38 Article(s)
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COHERENCE OPTICS and STATISTICAL OPTICS
Effects of Coherent and Incoherent Light Sources on Resolution of Bessel Beam Imaging System
He Yanlin, Chen Ziyan, and Wu Fengtie
The effects of the coherent and incoherent light sources on the resolution of imaging system are studied in the process of non-diffracting beam imaging. In the limited diffraction imaging system, the formula of point spread function (PSF) of the imaging system is derived by the diffraction integral theory and Fourier oThe effects of the coherent and incoherent light sources on the resolution of imaging system are studied in the process of non-diffracting beam imaging. In the limited diffraction imaging system, the formula of point spread function (PSF) of the imaging system is derived by the diffraction integral theory and Fourier optical theory. By simulating and comparing the different PSFs, it is found that the PSF is more concentrated and the imaging quality is better under the condition of incoherent light sources. He-Ne laser coherent light with the wavelength of 632.8 nm and incoherent light of blue light LED with the center wavelength of 458.5 nm and full width at half-maximum of 24.5 nm are used for experiment as light source, and Zemax software is used to simulate. Comparing the experimental and the numerical simulation results, the thickness of the stripes image of incoherent source is more uniform, clearer and its resolution is higher. The experimental results are consistent with theoretical analysis and numerical simulation results..
Laser & Optoelectronics Progress
- Publication Date: Aug. 30, 2016
- Vol. 53, Issue 9, 90301 (2016)
Detectors
Narrowband Detection Waveband Selection for Infrared Warning Satellites Based on Synthetic Signal-to-Noise Ratio
Yuan Zhiwei, Huang Shucai, Xiong Zhigang, and Tang Yidong
Based on the wideband detection model, the accuracy and the volumes of spectral data combined with the narrowband information are applied in targets recognition, and then a new method to select the narrow detection waveband of infrared warning satellites based on synthetic signal-to-noise ratio is proposed. According tBased on the wideband detection model, the accuracy and the volumes of spectral data combined with the narrowband information are applied in targets recognition, and then a new method to select the narrow detection waveband of infrared warning satellites based on synthetic signal-to-noise ratio is proposed. According to the narrowband imaging principle of warning satellites, a narrowband filter is added in the imaging system. The radiance from target and background, the dark current noise as well as the thermal noise from detector are considered, and then a new complete model for calculating synthetic signal-to-noise ratio is proposed. Taking the defense support program（DSP） satellite as an example, the central waveband of 2.726, 2.835, 3.012, 4.339 μm with the detection bandwidth of 10 nm, as detection waveband, is selected to calculate the synthetic signal-to-noise ratio spectra of tail at various altitudes..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 90401 (2016)
Holography
Computer-Generated Hologram Design for High-Precision Aspherical Surface Testing
Gao Songtao, Wu Dongcheng, and Yu Changsong
At present, aspherical elements are usually used to improve imaging quality and degrade complexity of system in the high numerical aperture (NA) projected lithography objective. However, high-precision aspherical surface testing has been a major problem in the field of optical detection. It is also the key factor whichAt present, aspherical elements are usually used to improve imaging quality and degrade complexity of system in the high numerical aperture (NA) projected lithography objective. However, high-precision aspherical surface testing has been a major problem in the field of optical detection. It is also the key factor which restricts the fabrication of high NA projected lithography objective. To solve this problem and aim at high NA projected lithography objective in the even of a high order asphere, the relationship and the calculating method between the phase and spatial frequency of computer-generated hologram (CGH) are discussed in the paper first. Then, by using a point source illumination mode, the methods of choosing key CGH design parameters and avoiding the interference of non-working order diffraction rays are analyzed in detail. Lastly, a CGH is fabricated using the design parameters chosen from this paper, and the asphere is tested by this CGH precisely. The root mean square value of the aspheric surface′s convergence precision eventually reaches 0.46 nm after several fabricating and testing iterations..
Laser & Optoelectronics Progress
- Publication Date: Aug. 20, 2016
- Vol. 53, Issue 9, 90901 (2016)
Image Processing
Research of Hyperspectral Image Classification Based on Hierarchical Sparse Representation Feature Learning
Li Tie, Sun Jinguang, Zhang Xinjun, and Wang Xing
A method of classification based on hierarchical sparse representation feature learning as hierarchical discriminative feature learning algorithm is developed for hyperspectral image classification. The spatial-pyramid-matching model is used, and the sparse codes learned from the discriminative features are obtained byA method of classification based on hierarchical sparse representation feature learning as hierarchical discriminative feature learning algorithm is developed for hyperspectral image classification. The spatial-pyramid-matching model is used, and the sparse codes learned from the discriminative features are obtained by max pooling in each layer of the two-layer hierarchical structure. The representation of features achieved by the proposed method are more robust and discriminative for the classification. The proposed method is evaluated on two hyperspectral datasets, and the results show that the proposed method has good classification accuracy..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 91001 (2016)
Hyperspectral Image Destriping Based on Adaptive Unidirectional Variation
Liu Yamei
Stripe noise disturbs the quality of hyperspectral images (HSIs), and decreases the precision and robustness of the downstream data analysis. After analyzing the characteristics of stripe noise of HSIs, that is, stripe noise is directional and noise intensities vary in each band, a new destriping method based on the adStripe noise disturbs the quality of hyperspectral images (HSIs), and decreases the precision and robustness of the downstream data analysis. After analyzing the characteristics of stripe noise of HSIs, that is, stripe noise is directional and noise intensities vary in each band, a new destriping method based on the adaptive unidirectional variation is proposed. On the basis of the unidirectional variation model, an energy function with a coupling term is constructed, which is then optimized iteratively with the gradient descent method. Experimental results demonstrate that the mean equivalent number of looks of real HSIs improves from 26.49 to 85.61, and the mean improvement factor of radiometric quality increases to 9.34 dB. Compared with the conventional methods, the proposed method can adapt to the spectrally varying stripe noise intensities, and is capable of removing stripe noise without loss of detail information and improving the image quality..
Laser & Optoelectronics Progress
- Publication Date: Aug. 26, 2016
- Vol. 53, Issue 9, 91002 (2016)
Color Image Encryption Algorithm Based on DNA Sequence Operation and Fractional Order Chen Hyper-Chaotic System
Yao Lisha, Zhu Zhenyuan, and Cheng Jiaxing
According to the characteristics of color image encryption, in order to reduce the correlation of images, increase the key space and improve the security, the color image encryption algorithm based on DNA sequence operation and fractional order Chen hyper-chaotic system is proposed. The three-dimensional color image isAccording to the characteristics of color image encryption, in order to reduce the correlation of images, increase the key space and improve the security, the color image encryption algorithm based on DNA sequence operation and fractional order Chen hyper-chaotic system is proposed. The three-dimensional color image is transformed into three two-dimensional DNA sequence matrices. The chaotic sequences which is generated by fractional order Chen chaotic system are used to scramble the locations of elements from three DNA sequence matrices, and then divide three DNA sequence matrices into some equal blocks respectively. The proposed algorithm adds these blocks by using fractional order Chen chaotic system and DNA sequence addition operation. The encrypted color image by decoding the DNA sequence matrices and recombining the blocks. The simulation results and security analysis show that the proposed algorithm has the advantages of low space, short time, low correlation, big space of the key, high sensitivity of the key, high security and strong resist attacks ability compared with other image encryption algorithms..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 91003 (2016)
Imaging Systems
Sub-Pixel Rendering Algorithm of Improving Image Brightness
Feng Jun, Yan Limin, and Xia Mingzhi
Two sub-pixel rendering algorithms of RGBW arrangement structure are proposed. The algorithms can keep the same resolution as traditional RGB arrangement, and improve the image brightness. The image processing includes two algorithms: mapping algorithm from RGB to RGBW and sub-pixel rendering algorithm of RGBW. The imaTwo sub-pixel rendering algorithms of RGBW arrangement structure are proposed. The algorithms can keep the same resolution as traditional RGB arrangement, and improve the image brightness. The image processing includes two algorithms: mapping algorithm from RGB to RGBW and sub-pixel rendering algorithm of RGBW. The image receives new RGBW data from mapping algorithm of RGB to RGBW, and the algorithm improves the image brightness and keeps the color saturation. Sub-pixel rendering algorithm of RGBW makes the image realistic and soft, and it can reduce jagged sense. Simulation results show that the proposed RGBW arrangement and rendering algorithm can significantly improve the image brightness..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 91101 (2016)
Infrared Imaging Technology Based on Pixel-Level Digital Integration
Zhang Lisha, Liu Zhaojun, Ma Wenpo, Long Liang, and Wu Limin
In order to achieve high sensitivity infrared detection ability, the relationship between the charge handling capacity and the detection sensitivity is analyzed, and the pixel-level digital integration technique is introduced. By analyzing noise sources of the whole infrared imaging chains, the signal-to-noise-ratio moIn order to achieve high sensitivity infrared detection ability, the relationship between the charge handling capacity and the detection sensitivity is analyzed, and the pixel-level digital integration technique is introduced. By analyzing noise sources of the whole infrared imaging chains, the signal-to-noise-ratio model based on the pixel-level digital integration technique is established. The design of key parameters and the simulation of noise equivalent temperature difference model are accomplished combining with the application examples. The simulation results demonstrate that the pixel-level digital integration detection technique can break through the constraint that the traditional detection technology only has tens or hundreds of megabytes electron charge capacity, and it can realize the charge handling capability up to kilomega electronic magnitude and high sensitivity up to milli kelvin..
Laser & Optoelectronics Progress
- Publication Date: Aug. 18, 2016
- Vol. 53, Issue 9, 91102 (2016)
Effect of Ring Pupil on Telecentric Fabry-Perot Filter
Dong Jiangchen, and Jin Zhenyu
Astronomical Fabry-Perot filter has generally two kinds of optical mountings: collimated configuration and telecentric configuration. The effects of width to radius ratio (WRR) and F-number on aberration, central wavelength and bandwidth of the filter in telecentric configuration and ring pupil situations are studied. Astronomical Fabry-Perot filter has generally two kinds of optical mountings: collimated configuration and telecentric configuration. The effects of width to radius ratio (WRR) and F-number on aberration, central wavelength and bandwidth of the filter in telecentric configuration and ring pupil situations are studied. With numerical simulation method and ray tracing, the superposition result of complex amplitude on exit surface of filter is calculated. The numerical simulation result shows that there is no obvious degradation in aberration of filter when F-number is more than 50, the offset of central wavelength increases with the decrease of WRR, the bandwidth of transmission decreases with the decrease of WRR, and the offset of central wavelength and bandwidth both decrease with the increase of F-number. When F-number is relatively small, like 100, the larger field of view and bandwidth as narrow as 5.6 pm can be obtained at the same time, which will be one of the advantages of giant ring solar telescope..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 91103 (2016)
Distribution of Earth-Atmosphere Radiation on Key Component of Space Based Telescope - Sunlight Baffle
Lu Lin, Wang Wei, Meng Qingyu, and Wang Dong
Suppression of stray light is a crucial part of space-based telescope (SBT) design. The suppression of earth-atmosphere radiation (EAR) is complicated. In order to analyze the EAR of SBT in its ambient environment, a computational model of EAR irradiance on sunlight baffle, which is one of the key components of SBT, isSuppression of stray light is a crucial part of space-based telescope (SBT) design. The suppression of earth-atmosphere radiation (EAR) is complicated. In order to analyze the EAR of SBT in its ambient environment, a computational model of EAR irradiance on sunlight baffle, which is one of the key components of SBT, is constructed by taking a typical SBT into consideration and using the irradiation transmission theory. Based on the as-constructed model, distribution character of EAR on baffle under various operating conditions is simulated. And radiant flux of primary and secondary EAR at light aperture of telescope is also calculated. The computation results indicate that sunlight baffle is the major stray light source for SBT working on low earth orbit (LEO), and the secondary EAR from sunlight baffle affects much more than the primary EAR, which directly passes into telescope at light aperture. Therefore, serious consideration on the secondary EAR from sunlight baffle should be taken into the design of stray-light suppression..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 91104 (2016)
Instrumentation, Measurement and Metrology
Infrared Imaging Temperature Measurement for a Shielded Surface by Diffuse Medium
Liu Yongxiang, Zhang Jian, and Du Yongcheng
The issue of precise measurement of the infrared imaging temperature on a surface shielded by diffuse medium can be attributed to accurate calculation of the spectral bands optical depth of the medium at which the infrared image works. Infrared imagery temperature of the object shielded by the fine water sprays is takeThe issue of precise measurement of the infrared imaging temperature on a surface shielded by diffuse medium can be attributed to accurate calculation of the spectral bands optical depth of the medium at which the infrared image works. Infrared imagery temperature of the object shielded by the fine water sprays is taken as examples. A specific measurement method is presented by theoretical and experimental analysis. The geometrical parameters of diffuse medium (particle size, concentration, depth and so on) are measured by particle measuring system, the optical extinction coefficients combined with the theoretical calculation of Mie scattering are obtained, and the air transmissivity of the medium with Lambert-Beer law is calculated. Though setting the atmospheric transmission parameters in the infrared image, and complete the operation of accurate temperature measurement. Experimental results show that this method can accurately measure the surface temperature of the dispersion medium shield. As to the problem of the practical application, a method to estimate atmospheric transmissivity is proposed..
Laser & Optoelectronics Progress
- Publication Date: Aug. 23, 2016
- Vol. 53, Issue 9, 91201 (2016)
Detection Method of Surface Error Based on Laser Imaging
Li Yan, Li Hao, Gao Feng, and Zhu Yanyan
In order to solve the problems of low checking efficiency, low precision and high checking difficulty of surface caused by the oversize of sub-lens structure of solar energy concentrating mirror in the process of manufacture and assembly, a detection method of mirror surface shape error based on laser imaging is proposIn order to solve the problems of low checking efficiency, low precision and high checking difficulty of surface caused by the oversize of sub-lens structure of solar energy concentrating mirror in the process of manufacture and assembly, a detection method of mirror surface shape error based on laser imaging is proposed. In this method, image processing technologies are employed to analyze the imaging of laser dot matrix. The coordinate values of the mirror coordinate system are deduced when the corresponding incident light array occurs specular reflection by distinguishing the position of reflection imaging array points with different laser beams at the image plane coordinate system. The shape error of the whole reflecting surface is obtained by substituting the above incident point array coordinate values into standard paraboloidal equation to fit and calculating with the steepest descent iterative method. By comparing the measurement results of reflector with coordinate measurement machine, the result shows that the measurement accuracy of the proposed method can reach 0.8 mrad..
Laser & Optoelectronics Progress
- Publication Date: Aug. 24, 2016
- Vol. 53, Issue 9, 91202 (2016)
Non-Contact Optical Component Curvature Radius Detection System Based on Laser Scanning
Qin Ying, and Xu Jun
In this paper, a non-contact optical component curvature radius detection system based on laser scanning method is introduced. With this method, the automation degree of the curvature radius detection after rough grinding of the optical elements is greatly improved, and the software-hardware combined one-click surface In this paper, a non-contact optical component curvature radius detection system based on laser scanning method is introduced. With this method, the automation degree of the curvature radius detection after rough grinding of the optical elements is greatly improved, and the software-hardware combined one-click surface shape data are obtained as well. This system uses x/y-axis two-dimensional translation stage motion for grid scanning. Meanwhile, it measures surface shape camber based on laser scanning method and adds z axis lifting platform to increase the camber measurement range. Computer control program and the human-computer interaction interface are designed to make the system more flexible and convenient at later stage. The surface fitting algorithm is written, and the automatic acquisition and fitting of the optical surface shape data as well as the calculation of the relevant optical parameters are realized ultimately, then the detection of a variety of non-contact optical component surface shapes can be completed. Experiment results show that the system can get the required surface shape data whether the surface gap of optical components under test is beyond the measuring range of the laser head or not. After error processing, the measurement accuracy meets the testing requirements of rough grinding and is better than ±0.15 %..
Laser & Optoelectronics Progress
- Publication Date: Aug. 20, 2016
- Vol. 53, Issue 9, 91203 (2016)
Study on Dynamic Testing of Radio Frequency Identification Under Transportation Line Based on Photoelectric Technology
Liu Jialing, Yu Xiaolei, Zhao Zhimin, Lan Xiufeng, and Yu Yinshan
The dynamic performance of radio frequency identification (RFID) under transportation line based on photoelectric technology is investigated. By the laser ranging technology, a testing system is designed to measure the dynamic reading distance of RFID. The reading distance of single-tag or multi-tag system can be measuThe dynamic performance of radio frequency identification (RFID) under transportation line based on photoelectric technology is investigated. By the laser ranging technology, a testing system is designed to measure the dynamic reading distance of RFID. The reading distance of single-tag or multi-tag system can be measured indirectly, and the automatic measurement to the reading distance and literacy rate of RFID tags is realized. The single-tag and the multi-tag systems are respectively tested for their dynamic performances and the testing results are compared and analyzed. The results show that, in the process of testing the single-tag system, the dynamic reading performance of RFID tags is directly influenced by the material quality of conveyor belts. In contrast, in the process of testing the multi-tag system, the dynamic reading range of RFID tags decreases with the increase of the number of tags, and the collision tag can be detected accurately..
Laser & Optoelectronics Progress
- Publication Date: Aug. 25, 2016
- Vol. 53, Issue 9, 91204 (2016)
Lasers and Laser Optics
Anti-Detuning Laser with High Optical Axis Stability
Luo Xu, Wang Pengfei, Li Jiuxi, Hou Tianyu, and Chen Bin
The use of the double-rectangular-prism (DRP) cavity and the self-aligned feature of the rectangular prism (RP) make laser insensitive to shock, vibration and temperature fluctuations. When the laser repetition rate is 20 Hz, the output energy is 60 mJ, the pulse width is 11 ns, the divergence angle after ten times of The use of the double-rectangular-prism (DRP) cavity and the self-aligned feature of the rectangular prism (RP) make laser insensitive to shock, vibration and temperature fluctuations. When the laser repetition rate is 20 Hz, the output energy is 60 mJ, the pulse width is 11 ns, the divergence angle after ten times of beams expansion is 0.11 mrad, and the optical axis drift is less than 5 μrad in 30 s. The DRP cavity can effectively enhance the stability of laser optical axis. With a polarization coupling output, the coupling output rate is determined by the wave plate parameter and the RP material. Based on the theoretical study and the electromechanical integration design, a laser with high optical axis stability is successfully developed. The study has certain guiding significance for both the parameter design of DRP cavity and the engineering application of lasers with high optical axis stability..
Laser & Optoelectronics Progress
- Publication Date: Aug. 26, 2016
- Vol. 53, Issue 9, 91401 (2016)
Numerical Study of Repetitive Laser Shock Peening of Oxygen-Free High-Conductivity Copper
Wang Cheng, Hu Jiacheng, Xu Yangjian, and Wang Xiaogui
Based on the numerical simulation of laser shock peening (LSP) process of oxygen-free high-conductivity (OFHC) copper, the effect of numbers of repetitive peens on the residual stress field and the dimple in the LSP process is studied, and the mechanism of strengthening residual stress is discussed emphatically. The nuBased on the numerical simulation of laser shock peening (LSP) process of oxygen-free high-conductivity (OFHC) copper, the effect of numbers of repetitive peens on the residual stress field and the dimple in the LSP process is studied, and the mechanism of strengthening residual stress is discussed emphatically. The numerical results show that, with the increase of numbers of repetitive peens, both the plastic deformation of target materials and the dimple depth increase, and both the residual stress and the flow stress of target materials gradually approach to saturation. Compared with those by the third or fourth LSP, the influence on the size and distribution of the residual stress induced by the second LSP is more significant. The strengthening of the residual stress after repetitive LSPs is mainly attributed to the hardening history of target materials, and the residual stress induced by the previous LSP shows certain inhibition effect on the material hardening in the current LSP process..
Laser & Optoelectronics Progress
- Publication Date: Aug. 26, 2016
- Vol. 53, Issue 9, 91402 (2016)
Machine Vision
Corner Detection for Fisheye Checkerboard Images Based on Iterative Correction
Shen Xiajing, Cheng Mengjiao, Xiao Jiangjian, and Song Wenxiang
There is a challenging problem during camera calibration with fisheye lens using the traditional checkerboard corner detection method, and leads to low calibration precision of camera. So, an iterative correction checkerboard corner detection method for large distortion images is proposed. The main idea of this method There is a challenging problem during camera calibration with fisheye lens using the traditional checkerboard corner detection method, and leads to low calibration precision of camera. So, an iterative correction checkerboard corner detection method for large distortion images is proposed. The main idea of this method is step by step iterative estimation and optimization of camera parameters through several shots. The camera initial parameters are obtained using the images from the remote-center small-distortion region. The distortion compensation of near-distance large distortion is realized through space and coordinate transformation and pixel interpolation gray. On this basis, the corner points of image edges can be detected, and the corner coordinates corresponding to the near-distance large-distortion images are calculated based on the parameter mapping relationship. Simulation and real image experimental results show that the proposed method is simple to be implemented, and improves the quantity and quality of corner detection effectively, which can satisfy the practical application requirements..
Laser & Optoelectronics Progress
- Publication Date: Aug. 23, 2016
- Vol. 53, Issue 9, 91501 (2016)
Materials
Influence of Beam Polarizations on Holographic Fabrication of Triangular Photonic Crystals
Liang Wenyao, He Ruibin, Lin Dengrong, and Gong Jue
Based on the multiple beam interference principle, the common rules and influence factors in holographic fabrication of photonic crystals are studied. Furthermore, taking triangular lattice as an example, the polarization combinations influence on photonic crystal microstructures is studied by Matlab simulations. UsingBased on the multiple beam interference principle, the common rules and influence factors in holographic fabrication of photonic crystals are studied. Furthermore, taking triangular lattice as an example, the polarization combinations influence on photonic crystal microstructures is studied by Matlab simulations. Using symmetry of the beam configuration of triangular lattice, the influence of polarization combinations on the intensity maximum, minimum value and contrast under the equal intensity condition is studied by dividing ten kinds of polarization combinations into three groups. The influence rules of polarization change on the photonic crystal microstructures are further summarized. Finally, a set of optimal polarization combination for triangular lattice with optimal contrast is obtained..
Laser & Optoelectronics Progress
- Publication Date: Aug. 08, 2016
- Vol. 53, Issue 9, 91601 (2016)
Binding Energy of Bound Polaron and the Polaron Shift as the Functions of Composition x in Wurtzite ZnO/MgxZn1-xO Quantum Well Under the Built-in Electric Field
Zhao Fengqi, and Pan Hongyu
The influence of the built-in electric field on bound polaron binding energy and the polaron shift in a wurtzite ZnO/MgxZn1-xO quantum well are investigated using the improved Lee-Low-Pines (LLP) variational theory. The ground-state energy and binding energy, the contributions from different branches of optical phononsThe influence of the built-in electric field on bound polaron binding energy and the polaron shift in a wurtzite ZnO/MgxZn1-xO quantum well are investigated using the improved Lee-Low-Pines (LLP) variational theory. The ground-state energy and binding energy, the contributions from different branches of optical phonons to the energy and the binding energy are given as the functions of composition x. The anisotropic properties of dielectric constant, electron band mass, different branches of optical phonons frequencies, the optical phonon-electron and the impurity center interaction are considered in the numerical calculations. The results show that the influence of the built-in electric field on the binding energy and polaron shift is obvious, and the degree of the influence of the built-in electric field for the contributions of different phonon modes is different. The built-in electric field increases the total phonon contribution to the energy, but it significantly reduces the total phonon contribution to the binding energy. The binding energy with the built-in electric field rapidly decreases as increasing composition x, but the binding energy without the built-in electric field decreases slightly. The result also show that when increasing the composition x, the contributions of interface and confined phonons to the energy and the binding energy with and without the built-in electric field increase, the contributions of half space phonon reduce, and the total contributions of phonons to the energy increase. But the total contributions of phonons to the binding energy with and without the built-in electric field are different. The total contributions with the built-in electric field increase, while the total contributions without the built-in electric field decrease. In comparison with the zinc blende GaAs/AlxGa1-xAs quantum wells, the influence of optical phonons on the energy and the binding energy of bound polaron in a wurtzite ZnO/MgxZn1-xO quantum well is larger, and polaron shift is more obvious..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 91602 (2016)
Medical Optics and Biotechnology
Inversion of Optical Parameters of Biological Tissues Based on Improved Standard Diffusion Approximation Model
Xing Yongchun, Zhu Qibing, and Huang Min
Aiming at the nearly isotropic optical radiation and source-detector separation that is much longer than one transport mean free path in the standard diffusion approximation model, an improved model is developed by adding a point source at the air-biological tissue boundary to minimize the error close to the light sourAiming at the nearly isotropic optical radiation and source-detector separation that is much longer than one transport mean free path in the standard diffusion approximation model, an improved model is developed by adding a point source at the air-biological tissue boundary to minimize the error close to the light source. The effect of anisotropy and the ratio of μ′s/μa on diffuse distribution is analyzed, where μ′s is the effective scattering coefficient and μa is the absorption coefficient. The inversions of the optical parameters μa and μ′s are solved by using the improved model combining the nonlinear least squares method. The results show that compared with the standard diffusion approximation model, the improved model can reduce the error of diffuse distribution curve significantly and improve the inversion accuracy. The improved model provides similar inversion accuracy to the two-point source Delta-P1 approximation model and has no poor reproducibility of inversion parameters exhibited by the latter..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 91701 (2016)
Microscopy
Confocal Brillouin Spectrum Measurement Setup Based on Socket Programming
Zhong Kun, Wang Yun, Zhang Tao, and Zhao Weiqian
Compared with the spectrum test methods, such as the Raman spectroscopy, the Brillouin spectroscopy can reflect the mechanical properties including elasticity coefficient. By using a single-mode 532 nm laser as the excitation source, and a scanning multi-channel tandem Fabry-Perot interferometer to detect the BrillouinCompared with the spectrum test methods, such as the Raman spectroscopy, the Brillouin spectroscopy can reflect the mechanical properties including elasticity coefficient. By using a single-mode 532 nm laser as the excitation source, and a scanning multi-channel tandem Fabry-Perot interferometer to detect the Brillouin light, a confocal Brillouin spectrum test system has been successfully built. This system uses the socket port means with telecommunication function to acquire the photon counts and realize spectrum acquisition and display. This means is expected to be further applied to large-scale remote linkage setup related to confocal Brillouin imaging, and is a prosperous instrument design direction. Based on this confocal Brillouin spectrum test setup with socket programming, the Brillouin light of resin glass, silicon rubber and glass are obtained, and the corresponding longitudinal elasticity coefficients are calculated..
Laser & Optoelectronics Progress
- Publication Date: Aug. 24, 2016
- Vol. 53, Issue 9, 91801 (2016)
Nonlinear Optics
Enhancement of the Coupled Third Harmonic Conversion Efficiency in Non-Periodic Optical Superlattice
Zhang Lijuan, and Zhao Liming
The high conversion efficiency of coupled third harmonic generation (CTHG) is achieved in the non-periodic optical superlattice (NOS) which is devised by the nonlinear conjugate-gradient (NCG) method. For either the single wavelength case or the multiple wavelengths case, the conversion efficiency of CTHG is higher in The high conversion efficiency of coupled third harmonic generation (CTHG) is achieved in the non-periodic optical superlattice (NOS) which is devised by the nonlinear conjugate-gradient (NCG) method. For either the single wavelength case or the multiple wavelengths case, the conversion efficiency of CTHG is higher in the NOS structure than that in the aperiodic optical supperlattice (AOS) which is devised by the traditional simulated annealing method. Since the thickness of each domain is arbitrary and further optimization can be done by using NCG method, it is easier to achieve the optimal quasi-phase matching (QPM) in the NOS structure. The variation of conversion efficiency as a function of the optical wave propagating distance is calculated, and the results show that the conversion efficiency increases with the increase of the optical wave propagating distance, which indicates that the contribution of every domain on CTHG process is positive, and that the optical QPM can be achieved in the NOS structure..
Laser & Optoelectronics Progress
- Publication Date: Aug. 26, 2016
- Vol. 53, Issue 9, 91901 (2016)
Optics at Surfaces
Optical Transmission Characteristics of Embedded Metal Strip Based on Metal-Insulator-Metal Waveguide
Wei Lidan, Wang Hongqing, Yang Hongyan, Zheng Long, and Xiao Gongli
The effects of the length of the embedded metal strip and the width of the gap in the metal-insulator-metal waveguide structure on the optical transmission characteristics have been investigated using the finite-difference time-domain method. The result shows that, compared with the single straight waveguide, an obviouThe effects of the length of the embedded metal strip and the width of the gap in the metal-insulator-metal waveguide structure on the optical transmission characteristics have been investigated using the finite-difference time-domain method. The result shows that, compared with the single straight waveguide, an obvious transmission peak appears in this structure. Moreover, the Fabry-Perot cavity is generated by the gap between the metal strip and the metal at the top surface of the waveguide when the length of metal strip is relatively large. The high order resonant mode is stimulated, the energy is resonated continuously in the Fabry-Perot cavity, and multiple resonance peaks of attenuation are generated. Meanwhile, a surface plasmon polariton bandpass filter based on embedded double metal strip is proposed. The transmission of this filter can be down to zero except the resonant peak. In addition, the resonant wavelength can be adjusted by changing the various parameters such as the length of the metal strip..
Laser & Optoelectronics Progress
- Publication Date: Aug. 24, 2016
- Vol. 53, Issue 9, 92401 (2016)
Physical Optics
Propagation Properties of Anomalous Vortex Beam in Chiral Medium
Jiang Shengbao, and Tang Bin
The propagation properties of anomalous vortex(AV) beams in the chiral medium are numerically studied based on Collins diffraction integral formula. The results show that the AV beam can split into a left-handed circular polarization (LCP) light and a right-handed circular polarization (RCP) light when it is incident uThe propagation properties of anomalous vortex(AV) beams in the chiral medium are numerically studied based on Collins diffraction integral formula. The results show that the AV beam can split into a left-handed circular polarization (LCP) light and a right-handed circular polarization (RCP) light when it is incident upon a slab of a chiral medium. The change of the topological number directly affects the interference phenomenon caused by LCP light and RCP light at the beam center. The energy and the focusing effect of the AV beam increase with the increase of beam width..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 92601 (2016)
Generation and Interference of Vortex Beam Based on Spiral Phase Plate
Guo Miaojun, Zeng Jun, and Li Jinhong
The mechanism of vortex beam generated by spiral phase plate is expounded theoretically. The interference intensity expressions of the vortex beams, plane wave and spherical wave are derived and used to study the interference phenomenon of vortex beam. The corresponding relationship between topological charge and interThe mechanism of vortex beam generated by spiral phase plate is expounded theoretically. The interference intensity expressions of the vortex beams, plane wave and spherical wave are derived and used to study the interference phenomenon of vortex beam. The corresponding relationship between topological charge and interference pattern is obtained numerically. Meanwhile, the vortex beams are obtained by spiral phase plate experimentally, and the corresponding experimental results are presented, as well as the experimental results and numerical results are practically consistent. The results show that vortex beams with different topological charges correspond to uniqueness interference pattern, hence the topological charge of vortex beam can be intuitively detected by the interference pattern..
Laser & Optoelectronics Progress
- Publication Date: Aug. 26, 2016
- Vol. 53, Issue 9, 92602 (2016)
Simulation on Measurement of Topological Charge for Laguerre-Gauss Beams by Multiplexing
Yang Chunyong, Ding Liming, Hou Jin, Zhong Zhiyou, and Chen Shaoping
To solve the problem of topological charge measurement in vortex beams multiplexing transmission, a beam propagation model is established based on the extended Huygens-Fresnel diffraction integral, the Fourier optics and split-step beam propagation method. The multiplexing transmission of Laguerre-Gaussian beams in vacTo solve the problem of topological charge measurement in vortex beams multiplexing transmission, a beam propagation model is established based on the extended Huygens-Fresnel diffraction integral, the Fourier optics and split-step beam propagation method. The multiplexing transmission of Laguerre-Gaussian beams in vacuum is numerically simulated. Analysis of the phase distribution after the transmission in vacuum shows that a recognizable association exists between the phase distributions after two beams multiplexing and the topological charge of each multiplexing beam. Specifically, the number and the rotation direction of the central fans are the same as the smaller absolute value of topological charge, while the phase fork of external rim is equal to the difference absolute value of topological charge of each multiplexing beam, and the rotation direction of the external rim is the same as the one with bigger absolute value of topological charge. Therefore, the phase distribution can be used as a new method to measure the topological charge of vortex beams..
Laser & Optoelectronics Progress
- Publication Date: Aug. 26, 2016
- Vol. 53, Issue 9, 92603 (2016)
Measuring Jones Matrix of Arbitrary Orthogonal Basic Vectors Based on Stokes Space
Xiao Yueyu, Yang Huixiang, Xu Huaibao, Yan Jinkui, and Peng Lei
The relationship between the coherency matrix of arbitrary orthogonal basic vectors and their coordinates in the Stokes space is studied. It is revealed that the coherency matrix of different basic vectors can be concisely represented by their coordinates in the Stokes space. On this basis, a new method to directly meaThe relationship between the coherency matrix of arbitrary orthogonal basic vectors and their coordinates in the Stokes space is studied. It is revealed that the coherency matrix of different basic vectors can be concisely represented by their coordinates in the Stokes space. On this basis, a new method to directly measure the Jones matrix of an optical device is proposed and verified experimentally with a Faraday rotator. The Jones matrix of arbitrary basic vectors can be obtained without any transformation between the Stokes vectors and the Jones vectors, or between the Muller matrices and the Jones matrices. This provides a more convenient way to measure the polarization properties of optical devices and analyze the polarization performance of optical loops..
Laser & Optoelectronics Progress
- Publication Date: Aug. 28, 2016
- Vol. 53, Issue 9, 92604 (2016)
Quantum Optics
Solution of Master Equation of Density Matrix in Interaction System of Atom with Thermal Reservoir
Lu Daoming
The master equation of density matrix in the interaction system of atom with thermal reservoir can be solved by virtue of the Ket-Bra entangled state method and the analytical solution expression is shown. Atomic dipole squeezing effect in this system is numerically studied and the effects of the mean number of photonsThe master equation of density matrix in the interaction system of atom with thermal reservoir can be solved by virtue of the Ket-Bra entangled state method and the analytical solution expression is shown. Atomic dipole squeezing effect in this system is numerically studied and the effects of the mean number of photons in the thermal reservoir and the atomic spontaneous emission rate on the atomic dipole squeezing effect are discussed. The results show that the atomic dipole squeezing effect is weakened with the increase of the mean number of photons and the atomic spontaneous emission rate..
Laser & Optoelectronics Progress
- Publication Date: Aug. 26, 2016
- Vol. 53, Issue 9, 92701 (2016)
Quantitation of Frequency Upconversion Fluorescence Photons of Erbium Ions in Aluminum Germanate Glasses
Zhao Da, Tian Yameng, Zhao Xin, Wang Zhiqiang, and Lin Hai
The absolute spectral power distribution and net emission photon distribution of Er3+/Yb3+ doped waveguide-type aluminum germanate glasses are investigated, and the absolute quantification of upconversion fluorescence parameters of rare earth ion are realized. The performance of Er3+ ion upconversion fluorescence is chThe absolute spectral power distribution and net emission photon distribution of Er3+/Yb3+ doped waveguide-type aluminum germanate glasses are investigated, and the absolute quantification of upconversion fluorescence parameters of rare earth ion are realized. The performance of Er3+ ion upconversion fluorescence is characterized by integrating sphere and charge-coupled device detector system. The absolute spectral power distribution of upconversion fluorescence is analyzed. Further, the fluorescence parameters such as the number of the net emission photon and the quantum yields are derived. The results show that the effective diffusion rate of K+-Na+ ion-exchange in the glass sample of Er3+/Yb3+ doped aluminum germanate glasses in KNO3 fused salt at 380 ℃ is 0.077 μm2/min. The green light and red light centered at 548 nm and 661 nm are emitted after Er3+ illuminated by 975 nm pump light, and the red light is dominant emission. The output power and the net emission photon of dominant red emission are 47.86 μW and 16.03×1013 s-1 respectively, when the laser power density is 1227 W/cm2. Compared with the relative measurement method whose fluorescence quantum yield magnitude in germanate glass stays within the range of 10-6-10-5, absolute method for photon quantification can provide more accurate data, which significantly improves the accuracy and repeatability of test parameters for rare earth upconversion fluorescence in waveguide-type aluminum germanate glasses..
Laser & Optoelectronics Progress
- Publication Date: Aug. 24, 2016
- Vol. 53, Issue 9, 92702 (2016)
Reviews
Progress in Frequency-Doubled External-Cavity Surface-Emitting Lasers
Jiang Lidan, Zhang Xiaohua, Zhan Xiaohong, Zhu Renjiang, Jiang Maohua, and Zhang Peng
The intra-cavity frequency-doubled vertical external-cavity surface-emitting laser (VECSEL) has high intra-cavity circulation power and can obtain ideal frequency-doubling conversion efficiency. The progress in VECSEL is reviewed. The usage of different nonlinear crystals and the achieved harmonic wavebands obtained byThe intra-cavity frequency-doubled vertical external-cavity surface-emitting laser (VECSEL) has high intra-cavity circulation power and can obtain ideal frequency-doubling conversion efficiency. The progress in VECSEL is reviewed. The usage of different nonlinear crystals and the achieved harmonic wavebands obtained by different frequency-doubled VECSELs are summarized, and the tendency of VECSEL and the problems confronted in future work are discussed..
Laser & Optoelectronics Progress
- Publication Date: Aug. 28, 2016
- Vol. 53, Issue 9, 90001 (2016)
Review on Multi-Degree-of-Freedom Motion Error Measurement Methods for Rotary-Axis Laser
Yang Jing, Feng Qibo, and Li Jiakun
Rotary axis is considered as the basis for rotational motion. It is a key component in precision measuring, machining and controlling equipments, and it plays a crucial role in high-end manufacturing, aerospace, and optical analysis fields. Each rotary axis has six degree-of-freedom translational and rotational errors.Rotary axis is considered as the basis for rotational motion. It is a key component in precision measuring, machining and controlling equipments, and it plays a crucial role in high-end manufacturing, aerospace, and optical analysis fields. Each rotary axis has six degree-of-freedom translational and rotational errors. To improve the equipment accuracy, one of the commonly applied solutions is to measure the six degree-of-freedom errors and then to establish the error compensation model to compensate these errors. The progress in methods to measure the multi-degree-of-freedom motion errors in a rotary axis based on laser is reviewed, the principle, pros and cons of these methods are analyzed, and the trend in the field is discussed as well..
Laser & Optoelectronics Progress
- Publication Date: Aug. 24, 2016
- Vol. 53, Issue 9, 90003 (2016)
3~5 μm Optical Parametric Oscillator Technology
Dong Yijing, Ma Xiuhua, Li Shiguang, and Zhu Xiaolei
The methods of producing mid-infrared laser are introduced, and the latest progress of the mid-infrared laser output obtained by optical parametric oscillation technology at home and abroad is expounded importantly. The technical characteristics and problems of the optical parametric oscillator (OPO) based on nonlinearThe methods of producing mid-infrared laser are introduced, and the latest progress of the mid-infrared laser output obtained by optical parametric oscillation technology at home and abroad is expounded importantly. The technical characteristics and problems of the optical parametric oscillator (OPO) based on nonlinear crystals, including ZnGeP2(ZGP), KTiOAsO4(KTA) and periodically poled LiNbO3(PPLN), are analyzed. The developing tendency of the mid-infrared laser produced by optical parametric oscillator technology is discussed..
Laser & Optoelectronics Progress
- Publication Date: Aug. 26, 2016
- Vol. 53, Issue 9, 90004 (2016)
Progress in Infrared Supercontinuum Generation in Chalcogenide Glass Fibers
Wang Yingying, Dai Shixun, Luo Baohua, Zhang Peiqing, Wang Xunsi, and Liu Zijun
Since chalcogenide glasses show advantages of ultra-wide infrared transmittance range and extremely high linear and nonlinear refractive indices, chalcogenide glass fibers become the unique optical fiber host materials for mid-infrared and far-infrared supercontinuum generation. The research progress in infrared supercSince chalcogenide glasses show advantages of ultra-wide infrared transmittance range and extremely high linear and nonlinear refractive indices, chalcogenide glass fibers become the unique optical fiber host materials for mid-infrared and far-infrared supercontinuum generation. The research progress in infrared supercontinuum generation in conventional step-index chalcogenide glass fibers, chalcogenide microstructured optical fibers and fiber tapers is reviewed..
Laser & Optoelectronics Progress
- Publication Date: Aug. 24, 2016
- Vol. 53, Issue 9, 90005 (2016)
Scattering
Effect of Particle Shape on Particle Size Measurement in Multi-Wavelength Light Extinction Method
Li Tan, Su Mingxu, Chen Jun, and Cai Xiaoshu
The effect of non-spherical particles shape on particle measuring method based on multi-wavelength light extinction method is investigated. According to the generalized Mie scattering theory, the extinction section and extinction coefficient of spheroidal particles with different major and minor axes under different inThe effect of non-spherical particles shape on particle measuring method based on multi-wavelength light extinction method is investigated. According to the generalized Mie scattering theory, the extinction section and extinction coefficient of spheroidal particles with different major and minor axes under different incident angles are calculated by numerical simulation, and they are compared with the extinction characteristics of equivalent spherical particle. The extinction spectrum is calculated by combining with Lambert-Beer law, and the particle size of the spheroidal particles is inversed by regularization algorithm. Then the influence of the shapes of the spheroidal particles on particle size measurement result is analyzed. The results show that the change of spheroidal particle shape will bring significant deviation to the inversed particle size result compared with spherical assumption. In this paper, relative deviation can exceed 90% for submicron particles under shape parameter a/b of 5..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 92901 (2016)
Spectroscopy
Simultaneous Measurement of Film Thickness and Mass Fraction by Raman Spectroscopy
Wang Qin, Zhao Chang, Yang Huinan, Su Mingxu, and Cai Xiaoshu
Quantitative analysis of the film thickness and the mass fraction of urea solution is extremely crucial in relevant industrial processes. The traditional method can measure the film thickness or the mass fraction alone independently. A method to simultaneously measure the thickness and the mass fraction of urea solutioQuantitative analysis of the film thickness and the mass fraction of urea solution is extremely crucial in relevant industrial processes. The traditional method can measure the film thickness or the mass fraction alone independently. A method to simultaneously measure the thickness and the mass fraction of urea solution is proposed based on the Raman spectroscopy. Through setting the standard curves reflecting the dependence of the relative intensity of characteristic Raman peak (1004 cm-1, belonging to N-C-N symmetric stretching vibration) on the thickness and the mass fraction, mathematical models are established to retrieve the film thickness and the mass fraction of the urea solution. The results reveal that the intensity is linearly related to the thickness (2-10 mm) when the solution concentration is constant, and the average measurement error for the film thickness is 8.36%. The intensity is linearly related to the mass fraction (5%-40%) when the film thickness is constant, and the average measurement error for the mass fraction is 6.24%..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 93001 (2016)
Study on Photodissociation and Spectroscopy of Freon 113
He Zhongfu, Liu Yuzhu, Li Linghao, Wang Yali, Luo Lihai, and Qin Chaochao
The time-of-flight mass spectrum of freon F-113 (C2F3Cl3) has been obtained by other researchers′ experiment under action of a 800 nm sapphire femtosecond laser, and three major dissociation channels of C2F3Cl+3 are discovered by calculating the proportion of each peak in the mass spectrum and analyzing the detected frThe time-of-flight mass spectrum of freon F-113 (C2F3Cl3) has been obtained by other researchers′ experiment under action of a 800 nm sapphire femtosecond laser, and three major dissociation channels of C2F3Cl+3 are discovered by calculating the proportion of each peak in the mass spectrum and analyzing the detected fragment ions. The energy difference of each dissociation channel is calculated and the chlorine isotope abundance ratio of major ions in the mass spectrum approaches the natural abundance ratio of 3.13. Stable configurations of major ions in the C2F3Cl3 light dissociation process are obtained by the optimization at B3LYP/6-311G++(d,p) basis set level of Gaussian 09. The infrared spectrum and single point energy of each configuration are obtained through calculation of frequency and energy. The potential energy surface scan on stable configurations of C2F3Cl3 and C2F3Cl+3 obtained by the optimization at B3LYP/6-31G++(d,p) basis set level of Gaussian 09 shows that the activity of C—C (1-2) and C—Cl (2-3) bonds is stronger than that of C—Cl (1-5) and C—F (1-7,1-8,2-6) bonds in C2F3Cl+3. C—C (1-2) and C—Cl (2-3) bonds are easy to break and dissociate, which is in coincidence with the strongest or stronger peaks in the mass spectrum obtained by the experiment..
Laser & Optoelectronics Progress
- Publication Date: Aug. 29, 2016
- Vol. 53, Issue 9, 93002 (2016)
Nonlinear Spectral Recovery Based on Fast Gaussian Gridding
Shen Yan, Bai Caixun, Wang Hao, Zhou Jianqiang, and Li Jianxin
For the low precision of nonlinear spectral recovery of the Fourier transform spectrometer, a nonlinear spectral recovery method based on the fast Gaussian gridding (FGG) is studied. The theory of non-uniform Fourier transform based on FGG is studied and the simulation verifies the high recovery precision and the feasiFor the low precision of nonlinear spectral recovery of the Fourier transform spectrometer, a nonlinear spectral recovery method based on the fast Gaussian gridding (FGG) is studied. The theory of non-uniform Fourier transform based on FGG is studied and the simulation verifies the high recovery precision and the feasibility of the FGG method. A spectral measurement device of birefringent polarization interference is set up and the spectral recovery for the unequal-interval sampled interference signal is carried out. The spectrum recovered based on the FGG method is basically consistent with the result of spectrometer. The theoretic simulation and experimental results show that the nonlinear spectral recovery can be realized effectively by the FGG method..
Laser & Optoelectronics Progress
- Publication Date: Aug. 12, 2016
- Vol. 53, Issue 9, 93003 (2016)
X-Ray Optics
Segmental Multi-Energy Computed Tomography Imaging Based on Wavelet Analysis
Sun Chunxia, Pan Jinxiao, and Chen Ping
The X-ray multi-energy computed tomography (CT), which primarily reconstruct images by collecting projections obtained by repeated circular scans at different energy, shows low scan efficiency and large dose of radiation exposure. The segmental multi-energy CT is studied. The tube voltage in every arc of a traditional The X-ray multi-energy computed tomography (CT), which primarily reconstruct images by collecting projections obtained by repeated circular scans at different energy, shows low scan efficiency and large dose of radiation exposure. The segmental multi-energy CT is studied. The tube voltage in every arc of a traditional circular trajectory CT scan is different to obtain the segmental multi-energy projection. Based on the accurate location of high frequency in the wavelet analysis, the gray-step of segmental multi-energy projection is corrected by the gray-step height of low frequency, and the segmental multi-energy CT imaging is realized. The simulation results indicate that compared with the hardening artifact correction mode, the method based on wavelet analysis eliminates the gray-step artifact, extends the energy spectrum information, and improves the reconstructed image contrast and hardening artifacts effectively..
Laser & Optoelectronics Progress
- Publication Date: Aug. 24, 2016
- Vol. 53, Issue 9, 93401 (2016)
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