Journals >Laser & Optoelectronics Progress
Contents
2015
Volume: 52 Issue 5
34 Article(s)
Export citation format
Atmospheric Optics and Oceanic Optics
Micro Pulse Lidar Observations of Aerosols in Nanjing
Zhu Cunxiong, Cao Nianwen, Yang Fengkai, Yang Shaobo, and Xie Yinhai
The aerosol measurement by micro-pulse lidar(MPL) system is taken in Nanjing Comprehensive Observation Base of China Meteorological Administration in the north suburb of Nanjing. The variation of aerosol extinction coefficient profiles and depolarization ratio profiles indicate that the depolarization ratio of aerosolsThe aerosol measurement by micro-pulse lidar(MPL) system is taken in Nanjing Comprehensive Observation Base of China Meteorological Administration in the north suburb of Nanjing. The variation of aerosol extinction coefficient profiles and depolarization ratio profiles indicate that the depolarization ratio of aerosols in clear atmosphere, mist and water cloud have similar values, but the value of ice cloud depolarization ratio is larger than all of them. Nearly 50 times inversion results of experimental data during January to June in 2009 show that the depolarization ratio is concentrated between 0 to 0.05 when the height of cloud base is below 4 km. While the height is above 4 km, this value is almost between 0.05 to 0.15. The higher of height cloud base is, the higher of the probability of larger depolarization ratio values is appeared. Comparing the inversion results of summer mist and winter dust in 2012, the results show that dust appears obvious boundary, while the characteristics of mist boundary is blurred. Dust's outbreak and dissipate can be monitored by combining spatial distribution and temporal distribution of extinction coefficient with change of depolarization ratio. Comparing the results of MPL and CE-318 sun photometer, the optical thickness of both instruments measured is consistent with the trends of time..
Laser & Optoelectronics Progress
- Publication Date: Apr. 25, 2015
- Vol. 52, Issue 5, 50101 (2015)
Fiber Optics and Optical Communications
Study on Micro-Bend Fiber Optic Pressure Sensor
Wu Lishuang
A new fiber-optic pressure sensor is studied. A nonlinear compensation method for optical fiber micro bend sensor by using strain nonlinear characteristics of trapezoidal springs and a way to overcome the instability of optical path loss by using differential detection are proposed. The principles of the fiber microbenA new fiber-optic pressure sensor is studied. A nonlinear compensation method for optical fiber micro bend sensor by using strain nonlinear characteristics of trapezoidal springs and a way to overcome the instability of optical path loss by using differential detection are proposed. The principles of the fiber microbend sensor with trapezoidal spring are introduced. Response curve of trapezoidal spring deformation at pressure of the aerodrome is nonlinear fitted, and the square curve is achieved. Atmospheric pressure from 0 to 0.1 MPa is experimentally tested to verify sensing characteristics. Results show that output voltages and gas pressures have good linearity in the fiber-optic pressure sensors，and pressure measurement sensitivity coefficient is about 2000 mV/MPa. It can meet the requirements of pressure measurement in monitoring of meteorology and aircraft height..
Laser & Optoelectronics Progress
- Publication Date: Apr. 23, 2015
- Vol. 52, Issue 5, 50601 (2015)
Bending Loss Model of Cosine-Shaped Waveguide
Zhang Ying, Wang Shuo, and Gao Yunlei
S-shaped bend waveguide is indispensable to realize the lateral displacement and connections in the integrated optical devices. The transmission losses of different S-shaped waveguides are analyzed, and the lowloss cosine shape mode is found. On the basis of the previous Marcuse theoretical conclusions of bending wavegS-shaped bend waveguide is indispensable to realize the lateral displacement and connections in the integrated optical devices. The transmission losses of different S-shaped waveguides are analyzed, and the lowloss cosine shape mode is found. On the basis of the previous Marcuse theoretical conclusions of bending waveguide, a curve fitting method is used and several approximate loss calculation formulas are obtained. By using the Matlab software, the loss graph is gotten. Then compared with the traditional low- slope model, the closest one to the theoretical model is found. The results show that the Guassian curve fitting method can better describe the cosine-shaped waveguide loss..
Laser & Optoelectronics Progress
- Publication Date: Apr. 25, 2015
- Vol. 52, Issue 5, 50602 (2015)
Long Period Fiber Grating Fabricated at 200 ℃ Based on High Temperature Metal Glue
Song Dawei, Zhao Wen, Liu Yanlei, Zhang Anna, Zhang Jianzhong, Sun Weimin, and Yuan Libo
A novel way to make long period fiber grating is proposed. Attaching fiber on a periodic ripple metal structure by high temperature metal glue at 200 ℃, a long period fiber grating is fabricated when the temperature of the combined structure declines to room temperature. The temperature characteristics of this kind of A novel way to make long period fiber grating is proposed. Attaching fiber on a periodic ripple metal structure by high temperature metal glue at 200 ℃, a long period fiber grating is fabricated when the temperature of the combined structure declines to room temperature. The temperature characteristics of this kind of grating are tested, and the change of resonance peak for grating spectrum in different temperatures is discovered and its mechanism is discussed. This kind of grating can be used as optical fiber filter and optical fiber attenuator. At last, the easier grating realization by changing the diameter of optical fiber is also discussed..
Laser & Optoelectronics Progress
- Publication Date: Apr. 21, 2015
- Vol. 52, Issue 5, 50603 (2015)
Virtual Infrastructure Planning in Optical Networks for Cloud Computing
Zhang Yinfa, Li Ming, Ren Shuai, Wang Jingyu, and Wang Kun
In the era of big data and cloud computing, the virtual infrastructure planning converged optical network resources and data center resources is the best way to solve the challenges facing optical networks. Two integer linear program models for virtual infrastructure planning are established with and without wavelengthIn the era of big data and cloud computing, the virtual infrastructure planning converged optical network resources and data center resources is the best way to solve the challenges facing optical networks. Two integer linear program models for virtual infrastructure planning are established with and without wavelength conversion capability. With dynamic service request, two objective functions of the two models: minimum joint power consumption and minimum network resource utilization rate, are simulated and compared with the power consumption and the blocking rate performance. The results show that, under light load conditions, the minimum joint power consumption has lower power consumption; under heavy loads, the minimum network resource utilization rate has lower power consumption; the minimum network resource utilization rate always has a lower blocking rate..
Laser & Optoelectronics Progress
- Publication Date: Apr. 24, 2015
- Vol. 52, Issue 5, 50604 (2015)
Holography
Phase Distortion in Object Wavefront Reconstructed by Adjustable Magnification Algorithms
Qian Xiaofan
The adjustable magnification object wavefront reconstruction algorithm effectively uses the space bandwidth product of digital holograms, but also introduces phase distortion. Mathematical expressions of the distortion phase correspond to each adjustable magnification algorithm are derived from present studies. The resThe adjustable magnification object wavefront reconstruction algorithm effectively uses the space bandwidth product of digital holograms, but also introduces phase distortion. Mathematical expressions of the distortion phase correspond to each adjustable magnification algorithm are derived from present studies. The results indicate that a quadratic phase distortion superimpose on the magnified object wavefront, no matter the wavefront is reconstructed from Fresnel or lensless Fourier transform digital holograms. The phase distortions of + 1 and -1 orders constructed wavefronts are conjugate complexes to each other. The phase distortions is generated by a spherical wave, and the radius of the wave is irrelevant to algorithm selection, but mainly determined by magnification and the object distance..
Laser & Optoelectronics Progress
- Publication Date: Mar. 26, 2015
- Vol. 52, Issue 5, 50901 (2015)
Image Processing
Image Edge Extraction Combined with Predator-Prey-AACO Algorithm
Hui Xiaowei, Chang Zhengying, Lin Sen, and Cao Yihua
In view of adaptive ant colony optimization (AACO) algorithm in image edge extraction often appears problems of low efficiency, and easily falling into the local extremum. An adaptive ant colony image edge detection algorithm combined with biological Predator-Prey behavior is proposed. The algorithm is combined with AAIn view of adaptive ant colony optimization (AACO) algorithm in image edge extraction often appears problems of low efficiency, and easily falling into the local extremum. An adaptive ant colony image edge detection algorithm combined with biological Predator-Prey behavior is proposed. The algorithm is combined with AACO algorithm and Predator-Prey behavior. Ant colony is divided into Predator and Prey species, AACO algorithm is used to search the two species in the initial stage, after a certain number of iterations, the two species enter the exclusion stage. The method of automatic threshold is used to extract image edge. Experimental results show that compared with AACO algorithm and Canny algorithm, in terms of accuracy, image edge extrated by the proposed algorithm is better than the edge extracted by the first two algoritms. Meanwhile, it maintains fast convergence characteristic of AACO algorithm, and overcomes its shortcoming of easily falling into local extremum. So image edge can be effectively detected by it..
Laser & Optoelectronics Progress
- Publication Date: Apr. 10, 2015
- Vol. 52, Issue 5, 51001 (2015)
Image Scratch Detection Research Based on Adaptive Binary Tree
Zhou Lin, and Yang Na
In order to improve the quality of image scratch detection, adaptive binary tree algorithm is proposed. Scratch area is determined by projection of image, image sharpening is operated on mask. Gray of image scratch in neighborhood is divided using cluster method, the result is used as input node of binary tree, image pIn order to improve the quality of image scratch detection, adaptive binary tree algorithm is proposed. Scratch area is determined by projection of image, image sharpening is operated on mask. Gray of image scratch in neighborhood is divided using cluster method, the result is used as input node of binary tree, image pixel value is divided into eight stages of binary tree, characteristics of binary tree traverse of the feature pixel, adaptive threshold merge the region of the scratch in neighborthood. Algorithmic process is described. Experimental simulation shows the proposed algorithm can accurately detect the location and direction of the scratch, and is good for qualitative detection index..
Laser & Optoelectronics Progress
- Publication Date: Apr. 28, 2015
- Vol. 52, Issue 5, 51002 (2015)
Research about Method of Simulating True Color Image for Remote Sensing Image Lack of Blue Band
Xu Huixi, Chen Yunhao, and Xue Wanrong
True color images can not be synthetized due to some remote sensing data missing blue band. A method of simulating true color remote sensing image is proposed. The MODIS land surface reflectivily product (MOD09) is used as reference image where to select pixel samples, and a non- linear regression analysis model is acqTrue color images can not be synthetized due to some remote sensing data missing blue band. A method of simulating true color remote sensing image is proposed. The MODIS land surface reflectivily product (MOD09) is used as reference image where to select pixel samples, and a non- linear regression analysis model is acquired through a back- propagation (BP) artificial neural network that used to fit the spectral reflectance relationship among the blue band and red, or green and near-infrared bands. Then Landsat TM/MSS and SPOT- 5 blue bands are simulated with the trained fitting model, and a natural- color image is acquired. The experimental result shows that using the BP neural network model, the blue band of a multispectral image is well simulated and even the atmospheric effect of the blue band is removed. Thus a more realistic and informative natural- color image is acquired. The research results further extend the research depth on remote sensing image band simulation model based on the image-image relationship..
Laser & Optoelectronics Progress
- Publication Date: Apr. 10, 2015
- Vol. 52, Issue 5, 51003 (2015)
High-Precision Extended Object Tracking Based on Region Feature Matching
Zhang Jianwei
In order to track extended object more precisely, a high-precision extended object tracking method is proposed based on maximally stabel extremal regions (MSER) feature, according to binarization with sampling multithreshold, the MSERs are detected in a region of extended object, if area change rate of MSER meets centrIn order to track extended object more precisely, a high-precision extended object tracking method is proposed based on maximally stabel extremal regions (MSER) feature, according to binarization with sampling multithreshold, the MSERs are detected in a region of extended object, if area change rate of MSER meets centroid precision condition, the MSER is picked out. And MSER in next frame are extracted and matched with the MSER in previous frame, the centroid of the MSER matched is next tracking position. Experimental results show that the proposed tracking method can improve the stabilization and precision of extended object tracking, if area change rate of MSER meets the certain condition, the tracking precision is better than 0.1 pixel, and the time consumption reduces by 3/4..
Laser & Optoelectronics Progress
- Publication Date: May. 01, 2014
- Vol. 52, Issue 5, 51004 (2015)
Imaging Systems
Error Correction of Optical Axis at an Angle Shooting in Two-Dimensional Digital Speckle Correlation Method
Mei Xiao, Xie Dongping, and Qiao Zhen
In order to solve the error problem caused by misalignment of the lens optical axis and the target surface for two-dimensional digital speckle inclined axis measurement at a close range. A simple and effective lens distortion correction formula based on optical principle under different angles is worked out to modify tIn order to solve the error problem caused by misalignment of the lens optical axis and the target surface for two-dimensional digital speckle inclined axis measurement at a close range. A simple and effective lens distortion correction formula based on optical principle under different angles is worked out to modify the testing strain and at last the data correction effectiveness of calibraton strain formula is verified by standard specimen under compressive and tensile tests. The results show that the proposed method can eliminate the effect of misalignment distortion whose error is not exceed 9.24% so that the efficiency and accuracy of two-dimensional digital speckle correlation technology are improved..
Laser & Optoelectronics Progress
- Publication Date: Apr. 17, 2015
- Vol. 52, Issue 5, 51101 (2015)
Instrumentation, Measurement and Metrology
Subaperture Cophasing Technique of Segmented Mirror
Cao Rui, Zhao Zhiliang, Zheng Liehua, Zhang Zhihua, Chunyu Yongxi, and Zheng Wanguo
To realize co- phase of segmented asphere aperture, a calculation system is build up for testing and alignment segmented mirrors. Curve fitting the surface data of the paraboloid mirror is made to establish coordinate matrix. The position deviation of sub-apertures is calculated by using transformation matrix. The simuTo realize co- phase of segmented asphere aperture, a calculation system is build up for testing and alignment segmented mirrors. Curve fitting the surface data of the paraboloid mirror is made to establish coordinate matrix. The position deviation of sub-apertures is calculated by using transformation matrix. The simulation result shows that the segmented aperture achieves the initial accuracy. A two wave-length interferometer is used to detect the 600 mm paraboloid segmented aperture. Depends on the tilt error calculated form the surface data, the segmented aperture position deviation can be limited in the accuracy of a single aperture λ /15..
Laser & Optoelectronics Progress
- Publication Date: Mar. 26, 2015
- Vol. 52, Issue 5, 51201 (2015)
Research on Randomly Phase Shifting Surface Measurement Based on Least-Squares Iteration
Li Dong, Jiang Hongzhen, Liu Yong, and Liu Xu
In phase shifting interferometry, surface measurement error will exist due to the phase shifting error resulted from the system or environment. The principle of the least-squares iterative algorithm with randomly phase shifting is introduced. The original surface can be reconstructed with high accuracy by iteration in In phase shifting interferometry, surface measurement error will exist due to the phase shifting error resulted from the system or environment. The principle of the least-squares iterative algorithm with randomly phase shifting is introduced. The original surface can be reconstructed with high accuracy by iteration in the numerical simulation. The phenomenon that the reconstructed surface may be inversed to the actual one because of the randomly phase shifting is analyzed. It is proposed that the phase shifting orientation should be known in this algorithm to achieve correct results. Experiments are carried out for verification. The calibration method of the phase shifting direction of the interferometer is indicated..
Laser & Optoelectronics Progress
- Publication Date: Mar. 24, 2015
- Vol. 52, Issue 5, 51202 (2015)
Mathematical Model Research of Star Image Energy Distribution of Star Tracker
Wang Fan, Chang Jun, Hao Yuncai, and Niu Yajun
In order to obtain an accurate centroiding algorithm, it is inappropriate to directly regard star image energy distribution as the Gaussian distribution because of the upgrading demand of ultra- high precision star tracker. It is urgent to study the actual star image energy distribution. This paper studies the theory oIn order to obtain an accurate centroiding algorithm, it is inappropriate to directly regard star image energy distribution as the Gaussian distribution because of the upgrading demand of ultra- high precision star tracker. It is urgent to study the actual star image energy distribution. This paper studies the theory of mathematical statistics about discrete data model deviating from the normal distribution. The skew Gaussian distribution is proposed to describe star image energy distribution of high precision star tracker. Both simulation and measuring experiments prove that the actual distribution of the star image get closer to the skew Gaussian distribution. The results can be used to guide the research of the precise correction algorithm of the star tracker which can correct the coordinates of the centroid..
Laser & Optoelectronics Progress
- Publication Date: Mar. 24, 2015
- Vol. 52, Issue 5, 51203 (2015)
Study of Defocus Compensation Algorithm to Improve the Accuracy of Measuring the Radius of Curvature
Peng Shijun, Su Dongqi, and Miao Erlong
Based on vertical Fizeau interferometer for radius of curvature (ROC) measurement system, a simple null position power compensation algorithm for defocus at cat′s eye position and confocal position is proposed to improve the measurement accuracy of ROC. The linear relationship between defocus of the wave- front aberratBased on vertical Fizeau interferometer for radius of curvature (ROC) measurement system, a simple null position power compensation algorithm for defocus at cat′s eye position and confocal position is proposed to improve the measurement accuracy of ROC. The linear relationship between defocus of the wave- front aberration and the offset of tested surface is theoretically analyzed. And the theory line slope between the two is got. The results show that between power value at cat′ s eye and confocal null position and tested surface position offset is the linear relation. And the fitting line slope of experiment is consistent with the theoretical value. Furthermore, radius of curvature measurement precision is improved by an order of magnitude with using the defocus compensation algorithm when the tested surface with some defocus at confocal position..
Laser & Optoelectronics Progress
- Publication Date: Mar. 29, 2015
- Vol. 52, Issue 5, 51204 (2015)
Detection of Double Acousto-Optical Modulators Difference Frequency Based on Spectrum Correction
Li Yang, Xiangli Bin, Zhang Wenxi, Huang Min, Wu Zhou, and Kong Xinxin
In order to carry out high precision detection of frequency shift error of the acousto-optical modulator (AOM), a heterodyne interferometer detection method and an experimental system are designed. By measuring the frequency of the heterodyne interference signal, the actual difference frequency of the double AOM can beIn order to carry out high precision detection of frequency shift error of the acousto-optical modulator (AOM), a heterodyne interferometer detection method and an experimental system are designed. By measuring the frequency of the heterodyne interference signal, the actual difference frequency of the double AOM can be obtained. Spectrum correction algorithm using Hanning window is used for precise frequency correction. The relationship between detection accuracy of the difference frequency and sampling number by signals with different SNR is simulation analyzed, and the difference frequency of a pair of AOMs by designed experimental system is also detected. The simulation and experimental results show that the detection accuracy of the method used for difference frequency of double AOMs is better than 2 Hz. The method can provide valid reference for error analysis of high precision heterodyne detection system for application..
Laser & Optoelectronics Progress
- Publication Date: Mar. 24, 2015
- Vol. 52, Issue 5, 51205 (2015)
Experimental Measurement of Optical Constant of Biodiesel by Double Optical Pathlength Transmission Method
Wang Chengchao, Li Xingcan, Tan Jianyu, and Liu Linhua
The optical constant of biodiesel plays an important role in quantitatively and qualitatively analyzing its individual constituent, judging the mixed level with diesel fuel, and studying the intrinsic mechanism of radiation transfer. Transmittance model of the three-layer-plate structure (optical glass -biodiesel -optiThe optical constant of biodiesel plays an important role in quantitatively and qualitatively analyzing its individual constituent, judging the mixed level with diesel fuel, and studying the intrinsic mechanism of radiation transfer. Transmittance model of the three-layer-plate structure (optical glass -biodiesel -optical glass) is derived based on the ray trace method. Experimental measurement by double optical pathlength transmission method is conducted to study the temperature dependence of optical constant of biodiesel in the spectral range from 300 nm to 2500 nm. The results show that the refractive index of biodiesel decreases linearly with temperature increasing from 20 ℃ to 60 ℃, but the absorption index is less affected. Moreover, five main absorption peaks of biodiesel are observed at 1200, 1390, 1750, 2150 and 2300 nm, which are due to overtones and combinations of C—H stretching vibration of various chemical groups. Compared with ordinary vegetable oil, absorption peaks of the biodiesel exhibit the same locations but different amplitudes..
Laser & Optoelectronics Progress
- Publication Date: Apr. 28, 2015
- Vol. 52, Issue 5, 51206 (2015)
Lasers and Laser Optics
Experimental Study of Cavitation Bubble and Shock Wave Induced by Q-Switched Focused Laser Pulse Underwater
Lü Tao, Chen Fang, and Zhang Wei
To investigate cavitation effect induced by Q-switched focused laser pulse underwater, the influence of initial radius of cavitation bubble and adiabatic exponent on kinetics of cavitation bubble has been analyzed theoretically. It indicates that the initial radius affects the radius of dynamic bubble. With the increasTo investigate cavitation effect induced by Q-switched focused laser pulse underwater, the influence of initial radius of cavitation bubble and adiabatic exponent on kinetics of cavitation bubble has been analyzed theoretically. It indicates that the initial radius affects the radius of dynamic bubble. With the increase of initial radius, the bubble′s resonance period and the maximal radius will also increase. The maximal bubble radius increases with the increase of adiabatic exponent. Compared with initial bubble radius, the adiabatic exponent affects bubble dynamics less significantly. The bubble resonance periods have no significant difference under different adiabatic exponents. Cavitation bubbles can be induced by Q-switched Nd∶YAG laser pulse focused underwater. Dynamic cavitation bubbles and plasma are captured by high-speed photography. At the same time, the acoustic signal is detected by a hydrophone. The experiment result shows that the highest energy of bubbles and shock waves exists mainly in the first two oscillations. At the second and third maximum radius, the bubble energy reaches 31.9% and 9.96% of the highest bubble energy which happens at the first maximum radius respectively, and the energy of shock waves at the second and third collapse reaches 51% and 16.8% of the highest energy respectively. Subsequently, the energy of bubble and shock wave is attenuated dramatically..
Laser & Optoelectronics Progress
- Publication Date: Apr. 10, 2015
- Vol. 52, Issue 5, 51401 (2015)
Design and Experimental Study of Tunable Dual-Frequency Nd∶YAG Laser with Large Frequency Difference
Xing Junhong, and Jiao Mingxing
In order to obtain the tunable dual-frequency laser with large frequency difference, a laser diode endpumped dual-frequency Nd∶YAG laser with tunable frequency difference has been designed, using the light splitting and polarizing functions of the polarizing beam splitter (PBS) to form perpendicular straight and right In order to obtain the tunable dual-frequency laser with large frequency difference, a laser diode endpumped dual-frequency Nd∶YAG laser with tunable frequency difference has been designed, using the light splitting and polarizing functions of the polarizing beam splitter (PBS) to form perpendicular straight and right angle standingwave cavities. Both cavities employ birefringent filters acting as laser axial mode selectors. The p-and s-component of 1064 nm laser light can therefore be forced to oscillate simultaneously in single longitudinal mode. The principles of single longitudinal mode selection by birefringent filter and the simultaneous oscillation of the dual-frequency laser have been theoretically analyzed, and the characteristics of Nd∶YAG laser with single longitudinal mode oscillation at 1064 nm and frequency difference tuning have been investigated experimentally. It has been observed experimentally that the frequency difference of the dual-frequency laser at 1064 nm is tunable in a range from 11.4 GHz to 168.6 GHz, the maximum frequency difference has reached the fluorescence line width of Nd∶YAG. Such a dual-frequency Nd∶YAG laser can be used for laser interferometric measurement, laser spectroscopy and other fields..
Laser & Optoelectronics Progress
- Publication Date: Apr. 28, 2015
- Vol. 52, Issue 5, 51402 (2015)
Outer Gear Sets Micro-Fabrication by Two-Photon Polymerization
Cui Lianhe
The micro-fabrication process of the homemade two-photon polymerization fabrication system is introduced, and the formability of the external gear set is studied at different exposure time. The two-photon polymerization micro-fabrication of the outer gear sets are realized in the photomer3015, and the microstructure ofThe micro-fabrication process of the homemade two-photon polymerization fabrication system is introduced, and the formability of the external gear set is studied at different exposure time. The two-photon polymerization micro-fabrication of the outer gear sets are realized in the photomer3015, and the microstructure of the gear sets is analyzed through scanning electron microscope (SEM). The results show that with the increase of exposure time, the formability of the gear sets is better. When the exposure time increases, the total fabrication time also increase. When the laser power is 0.3 mW and the exposure time is 10 ms, the two-photon polymerization micro-fabrication of the outer gear set with the tooth thickness of 2 mm and a resolution of 1.0 mm is successfully manufactured..
Laser & Optoelectronics Progress
- Publication Date: Mar. 29, 2015
- Vol. 52, Issue 5, 51403 (2015)
Machine Vision
Research on Three Dimensional Positioning Algorithm on Machine Vision Inspection System of the Nick Depth of Easy Open End
Huang Liu, and Yu Guiying
The nick depth of easy open end is a key parameter in ensuring high packaging quality. In order to realize automatic detection of easy open end in industrial production sites and improve the measurement accuracy and stability, a machine vision system based on light- section method is developed, which has a three dimensThe nick depth of easy open end is a key parameter in ensuring high packaging quality. In order to realize automatic detection of easy open end in industrial production sites and improve the measurement accuracy and stability, a machine vision system based on light- section method is developed, which has a three dimensional positioning function and an image measuring function.In view of the light- sectioning image properities, the geometrical relationship between the measuring position and the notch slope in the x-y plane is analyzed through experiments to offer a two dimensional location strategy for automatically detecting and adjusting the light projection position. Through analyzing six focusing functions for the light-sectioning images, unimodal and unbiased as evaluation standard an automatic focusing algorithm based on the sum of gray rate of change function as rough focusing function and Laplacian function as fine focusing function is proposed to adjust the notch location. Experimental results show that the proposed algorithm has the strong single peak feature, good stability and high sensitivity..
Laser & Optoelectronics Progress
- Publication Date: Apr. 28, 2015
- Vol. 52, Issue 5, 51501 (2015)
Materials
Effect of Refractive Index of Substrate on Fabrication and Optical Properties of Hybrid Au-Ag Triangular Nanoparticle Arrays
Ye Wencai, He Xiaomeng, Lin Zijie, Chen Huibin, Liu Jing, Cai Haoyuan, Cai Zelong, and Li Changwei
Based on the substrate of silica and different types of slides, the effect of refractive index of substrate on fabrication and optical properties of hybrid Au- Ag triangular periodic nanoparticle arrays is systematically investigated. The optical spectrum of localized surface plasmon resonance (LSPR) simulated by discrBased on the substrate of silica and different types of slides, the effect of refractive index of substrate on fabrication and optical properties of hybrid Au- Ag triangular periodic nanoparticle arrays is systematically investigated. The optical spectrum of localized surface plasmon resonance (LSPR) simulated by discrete dipole approximation (DDA) numerical method shows that the nanoparticle arrays can obtain better refractive index sensitivity (RIS) and figure of merit (FOM), when refractive index of substrate is 1.43 and 1.68, respectively. The nanosphere lithography (NSL) is used to fabricate the periodic nanostructure arrays. The experimental results demonstrate that when refractive index of substrate is 1.43 and 1.68, nanoparticles and substrate have better adhesive ability. Meanwhile, the nanoparticles both form a large-scale monolayer array with the hexagonally close-packed structure..
Laser & Optoelectronics Progress
- Publication Date: Apr. 03, 2015
- Vol. 52, Issue 5, 51601 (2015)
First-Principles Calculation of Electronic Structure and Optical Properties of Monolayer MoS1.89X0.11
Fan Menghui, Cai Xunming, Cen Weifu, Luo Zuifen, and Xie Quan
The electric structure and optical properties of monolayer MoS1.89X0.11 have been calculated by the first-principle pseudo-potential method based on density functional theory (DFT). The results show that monolayer MoS1.89X0.11 (X=P, Si, Al) turn to a p-type semiconductor and the conduction band bottom is moved to the dThe electric structure and optical properties of monolayer MoS1.89X0.11 have been calculated by the first-principle pseudo-potential method based on density functional theory (DFT). The results show that monolayer MoS1.89X0.11 (X=P, Si, Al) turn to a p-type semiconductor and the conduction band bottom is moved to the direction of low energy. The band gap of monolayer MoS2 of P-doped and Si-doped is turned from K-point to Γ point in the BZ. The band gap of monolayer MoS2 of Al-doped turned to an indirect semiconductor at K -Γ point. Through analyzing the density of states and decentralization of grid, the optical properties of monolayer MoS2 is changed for the variation of carrier concentration and the hybrid orbitals of impurity atoms with S-3p and Mo-4d, especially Al-doped is the most effect that the static dielectric constant and refractive index is increased and the energy loss function is reduced..
Laser & Optoelectronics Progress
- Publication Date: Apr. 24, 2014
- Vol. 52, Issue 5, 51602 (2015)
Medical Optics and Biotechnology
A New Element for Correcting Presbyopia—Intraocular Lens Based on Light Sword Element
Fan Ruoyu, and Liu Yongji
In order to get continuous and clear vision over a long distance for the presbyopic eyes, an intraocular lens (IOL) is introduced into the human eye model, and the IOL is designed according to the principle of light sword optical element (LSOE). Based on the method of numerical simulation in Matlab, the retina imaging In order to get continuous and clear vision over a long distance for the presbyopic eyes, an intraocular lens (IOL) is introduced into the human eye model, and the IOL is designed according to the principle of light sword optical element (LSOE). Based on the method of numerical simulation in Matlab, the retina imaging effect is analysed in terms of E figure, modulation transfer function (MTF) curve and the Strehl ratio under the object distance of 0~4D. The LSOE-based intraocular lens is compared with traditional reading glass and axicon, depending on the quality of compensation. The results show that the LSOE-based IOL achieves clear continuous imaging from reading distance (25 cm) to infinity. It also has an advantage on the imaging quality. And the impact caused by the change of pupil diameter is lower than other elements..
Laser & Optoelectronics Progress
- Publication Date: Apr. 28, 2015
- Vol. 52, Issue 5, 51701 (2015)
Nonlinear Optics
Controlling the Transition of Bright and Dark States via Dressing Effect and Phase of the Coupling Filed
Li Xiang, and Li Peiying
The influence on the probe transmission (PT) and four-wave mixing (FWM) signals in a Y-type four-level system is theoretically studied, which is induced by the four kinds of dressing effect (singly-dressed and parallel-, sequential-, nested-doubly-dressed) of the coupling field. Moreover, the changed relative phase indThe influence on the probe transmission (PT) and four-wave mixing (FWM) signals in a Y-type four-level system is theoretically studied, which is induced by the four kinds of dressing effect (singly-dressed and parallel-, sequential-, nested-doubly-dressed) of the coupling field. Moreover, the changed relative phase induced by the changed configuration of the coupling field also influences the signals. Numerical simulation results show that the transition between the two quantum effects of bright and dark states in PT and FWM signals can be achieved by the changed probe field detuning or the changed relative phase. Such detuning or phase controlled transition has potential applications in optical communication, quantum information processing and optoelectronic devices..
Laser & Optoelectronics Progress
- Publication Date: Apr. 25, 2015
- Vol. 52, Issue 5, 51901 (2015)
Research on Broadband Spectrum Distribution Based on Spontaneous Parametric Down Conversion
Gao Dongyang, Xia Maopeng, Hu Youbo, Liu Yan, Sheng Wenyang, Li Jianjun, and Zheng Xiaobing
Research on spectrum distribution of correlated photon optics-field has great significance in terms of the calibration for photoelectric detector in broadband spectrum based on spontaneous parametric down-conversion. An experiment is set up to measure the distribution of correlated photon broadband spectrum. A continuoResearch on spectrum distribution of correlated photon optics-field has great significance in terms of the calibration for photoelectric detector in broadband spectrum based on spontaneous parametric down-conversion. An experiment is set up to measure the distribution of correlated photon broadband spectrum. A continuous wave 355 nm laser and a photon counting system are used to pump the β -barium borate (BBO) crystal to product type I spontaneous parametric down-conversion in the regime of nonlinear and the spectrum distribution of correlated photon outside the BBO crystal is measured, respectively. The bandwidth of correlated photon spectrum in experiment is 259 nm (550~808 nm). The angle distribution result in experiment is in accordance with the theory prediction, with the angle distribution difference less than 2%. It is turned out that a broad band spectrum distribution from visible to near infrared exists with respect to correlated photon. It is promising to be applied to calibration for photoelectric detector in broadband spectrum..
Laser & Optoelectronics Progress
- Publication Date: Mar. 25, 2015
- Vol. 52, Issue 5, 51902 (2015)
Optical Devices
Application Research on LED-Based Tea Color Sorter Light Source Spectrum
Gan Ruting, Guo Zhenning, Lin Jieben, Wang Biaoming, and Liao Xuan
Based on the principle of light and matter interaction and the basic optical characteristics of agricultural products, a model for LED tea color sorter light source is studied to sort Tieguanyin tea and impurities, and the light source spectrum is studied and designed. By testing the spectral reflectance of the tea andBased on the principle of light and matter interaction and the basic optical characteristics of agricultural products, a model for LED tea color sorter light source is studied to sort Tieguanyin tea and impurities, and the light source spectrum is studied and designed. By testing the spectral reflectance of the tea and impurities, the wavelength at which the tea and impurities have the maximum reflectivity difference is chosen as the peak wavelength of LED light sources in the range of visible light. The combination of multicolor LEDs is used to match the spectra of tea color sorter light source, and the numerical ratio of combinational LED light sources is decided by the proportion of relative reflectivity difference between tea and impurities at each corresponding peak wavelength. The results show that the tea color sorter light source can improve the processing efficiency of tea sortering and enlarge the contrast between tea and impurities with higher luminous efficiency characteristics and long lifetime, and it is beneficial to the sorter process of tea. Therefore, the study lays foundation for subsequent development of new LED tea color sorter light sources used for other tea color sorting and spectral design for special LED-based light sources..
Laser & Optoelectronics Progress
- Publication Date: Apr. 28, 2015
- Vol. 52, Issue 5, 52301 (2015)
Optics at Surfaces
Research on Anti-Noise-Interference Method of Angle Scanning Surface Plasmon Resonance Sensor
Qi Pan, Ma Xiao, Zhang Zibang, Zhong Jingang, and Li Ying
The surface plasmon resonance (SPR) sensor is widely used in biology, medicine, chemistry, drug screening, environmental monitoring, and food safety. However, the SPR sensor system can be easily affected by device self noise of optical source and photoelectricity detector etc, and ambient lights noise during detectionsThe surface plasmon resonance (SPR) sensor is widely used in biology, medicine, chemistry, drug screening, environmental monitoring, and food safety. However, the SPR sensor system can be easily affected by device self noise of optical source and photoelectricity detector etc, and ambient lights noise during detections, where the ambient light noise is particularly obvious. So the operation of SPR sensor needs to be in a shading environment, which is not conducive for rapid detections. To solve this problem, the characteristics of ambient light noise are analyzed on the basis of self-developed angle scanning surface plasmon resonance sensor. A data processing method, which combines an arithmetic average filtering and a low- pass filtering, is innovatively put forward to suppress the noise under fluorescent lights illumination. The experimental results of phosphate buffered saline (PBS) buffer detection shows that the proposed method can offer accurate detection under fluorescent lights illumination. The error of measurement results is 0.0027% , relative to the results in a shading measurement. The proposed method can effectively enhance the anti interference ability to ambient light of the angle scanning SPR sensor. Moreover, it has good application and popularization value.网络出版日期<2015-04-29>.
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 52, Issue 5, 52401 (2015)
Numerical Study on the Transmission Properties and Sensing Performance of a Periodic Array of V-Type Opened Silver Tubes
Lin Shijie, Shen Yang, and Jin Chongjun
A periodic array of V-type opened silver tubes is proposed to serve as a refractive index sensor. The transmission properties of this structure are investigated via the finite-difference time domain method. Simulation results show that the transmission spectra of this structure have three tunable peaks when the electriA periodic array of V-type opened silver tubes is proposed to serve as a refractive index sensor. The transmission properties of this structure are investigated via the finite-difference time domain method. Simulation results show that the transmission spectra of this structure have three tunable peaks when the electric field of the incident light is perpendicular to the gap. The peaks are induced by the propagating surface plasmon resonance (PSPR) at the silver-quartz interface and two different localized surface plasmon resonances (LSPR), respectively. The influences of structure parameters, such as array period, the tube diameter, height and gap width, on the transmission peak wavelength and full-width at half-maximun (FWHM) are analyzed By optimizing the structure, it can serve as a LSPR sensor with a figure of merit of 13.2..
Laser & Optoelectronics Progress
- Publication Date: May. 07, 2015
- Vol. 52, Issue 5, 52402 (2015)
Reviews
Recent Advances in Microwave Photonics Systems Based on Brillouin Processing
Guo Yong, Qiu Qi, and Wang Zhiyong
Principles of stimulated Brillouin scattering (SBS) and microwave photonics(MWP) system based on Brillouin processing (BP) in optical fiber are summarized. Based on Brillouin-selective amplification (BSA) and Brillouin-selective suppression (BSS), some applications of BP are deeply analyzed, such as optical generation Principles of stimulated Brillouin scattering (SBS) and microwave photonics(MWP) system based on Brillouin processing (BP) in optical fiber are summarized. Based on Brillouin-selective amplification (BSA) and Brillouin-selective suppression (BSS), some applications of BP are deeply analyzed, such as optical generation of microwave signals, photonic frequency upconversion/downconversion and frequency multiplication of microwave signals, MWP complex-valued coefficients and single response filter, MWP phase shifter, and link performance improvement in radio-over-fiber (RoF) system. Advantages and disadvantages of BP in these applications are discussed, and some potential improvement projects are presented. Development trends and application prospects of BP in MWP and integrated microwave photonics (IMWP) are discussed..
Laser & Optoelectronics Progress
- Publication Date: Apr. 21, 2015
- Vol. 52, Issue 5, 50001 (2015)
Research Progress on Arrayed Waveguide Grating Chip for Micro Raman Spectrometer
Xu Yingchao, Wang Qingna, Lin Hongyi, and Zhu Wenzhang
The core component of the micro Raman spectrometer is its spectroscopic chip. It has the important meaning to develope the new spectroscopic chip the micro Raman spectrometer with microminiaturization, high machining accuracy and low cost. This work can help us to break the current foreign technology patent blockade anThe core component of the micro Raman spectrometer is its spectroscopic chip. It has the important meaning to develope the new spectroscopic chip the micro Raman spectrometer with microminiaturization, high machining accuracy and low cost. This work can help us to break the current foreign technology patent blockade and obtain intellectual property rights of our own country. Arrayed waveguide grating is originally used in the optical communication field. It is a new thought to arrayed waveguide grating as the spectroscopic chip for the micro Raman spectrometer. Arrayed waveguide grating has the advantages of small size, high precision, simple processing, and easy to mass production. The research progress on arrayed waveguide grating chip for micro Raman spectrometer at home and abroad is described and the corresponding analysis is made. In addition, an improved method is proposed for arrayed waveguide grating used for spectroscopic chip..
Laser & Optoelectronics Progress
- Publication Date: Apr. 29, 2014
- Vol. 52, Issue 5, 50002 (2015)
Spectroscopy
Qualitative Analysis of Molten Steel Based on SVM by LIBS
Yang Yousheng, Zhang Yan, Yang Youliang, and Ma Cuihong
Laser induced breakdown spectroscopy (LIBS) technology has the characteristics of speediness, noncontact, no need of sample preparation, which is very suitable for the online analysis of the converter steel composition, because the end-point can be determined by Si and Mn contents and temperature. A qualitative analysiLaser induced breakdown spectroscopy (LIBS) technology has the characteristics of speediness, noncontact, no need of sample preparation, which is very suitable for the online analysis of the converter steel composition, because the end-point can be determined by Si and Mn contents and temperature. A qualitative analysis of LIBS is proposed for analyzing the Si and Mn composition in molten steel. Laser excitation spectra are collected by spectrometer, and after the operations of pretreatment and peak searching, with the atomic spectra database (NIST) as the reference standard, the corresponding characteristics of spectral line wavelength and spectral intensity of Si and Mn are found out. Based on the powerful classification function of support vector machine (SVM), 210 sets of 245 sets of data collecting are used to get the support vector classification (SVC) model, which then predicts that 245 groups of data. The accuracy of the model is more than 98%, which can identify the corresponding wavelength of Si and Mn very well, and can be used under the condition of the same experimental conditions with significant reduction to the LIBS qualitative analysis time..
Laser & Optoelectronics Progress
- Publication Date: Apr. 23, 2015
- Vol. 52, Issue 5, 53001 (2015)
Research on Detecting CO with Quartz Enhanced Photoacoustic Spectroscopy Based on 2.33 μm Distributed Feed Back Laser
Hu Libing, Liu Kun, Wang Guishi, Wang Lei, Tan Tu, and Gao Xiaoming
The novel 2.33 μm distributed feed back laser is used to detect carbon monoxide with off-beam quartz enhanced photoacoustic spectroscopy (QEPAS). The parameters including modulation frequency, modulation amplitude are optimized. The signal of off-beam QEPAS versus concentration of carbon monoxide is investigated. Good The novel 2.33 μm distributed feed back laser is used to detect carbon monoxide with off-beam quartz enhanced photoacoustic spectroscopy (QEPAS). The parameters including modulation frequency, modulation amplitude are optimized. The signal of off-beam QEPAS versus concentration of carbon monoxide is investigated. Good linearity between off-beam QEPAS signal and concentration of carbon monoxide is obtained. A normalized noise equivalent absorption coefficient of 3 × 10-6 cm-1·W/ Hz is obtained with a 1 s time constant of lock-in amplifier..
Laser & Optoelectronics Progress
- Publication Date: Apr. 28, 2015
- Vol. 52, Issue 5, 53002 (2015)
Thin Films
Investigation of the Intrinsic Damage Mechanisms for Optical Thin Film in Vacuum Environments
Ling Xiulan, Wang Gao, and Liu Xiaofeng
The intrinsic damage mechanisms for optical thin film in vacuum environments is investigated through the inter- coupling process between optical film and environment and the thermal- mechanical damage process between laser and optical film. It is found that water vapor desorption of the film layers exposed to vacuum enThe intrinsic damage mechanisms for optical thin film in vacuum environments is investigated through the inter- coupling process between optical film and environment and the thermal- mechanical damage process between laser and optical film. It is found that water vapor desorption of the film layers exposed to vacuum environment results in the decrease of the refractive index and the thermal conductivity of the film layer and hence leads to the serious decrease of laser- induced damage threshold for e- beam evaporated porous coatings in vacuum..
Laser & Optoelectronics Progress
- Publication Date: Apr. 04, 2015
- Vol. 52, Issue 5, 53101 (2015)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20