Journals >Laser & Optoelectronics Progress
Contents
2016
Volume: 53 Issue 10
38 Article(s)
Export citation format
Detectors
Design and Analysis of Terahertz Wave Directional Antenna
Shi Xiang, Zhang Chao, Qian Songsong, and Xing Yexin
Aiming at the specific application of terahertz wave detection and communication, the four kinds of 0.36 THz terahertz wave directional antennas, including feed horn antenna, double paraboloid Cassegrain antenna, lens antenna and offset feed single reflector antenna, are respectively designed, analyzed, simulated and fAiming at the specific application of terahertz wave detection and communication, the four kinds of 0.36 THz terahertz wave directional antennas, including feed horn antenna, double paraboloid Cassegrain antenna, lens antenna and offset feed single reflector antenna, are respectively designed, analyzed, simulated and fabricated based on microwave and millimeter-wave directional antenna design and application. The design and analysis of the above several terahertz wave directional antennas can provide theoretical and practical basis for the directional detection and communication application of terahertz wave technique that is based on the microwave double frequency technique..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 100401 (2016)
Diffraction and Gratings
Phase Shift Shadow Moiré Demodulation Based on Normalized Principal Component Analysis
Du Hubing, and Ai Yongxu
Conventional phase shifting shadow moiré profilometry usually needs more phase shifting images to demodulate the measurement phase because of the nonlinear phase shifting. The data sampling process is time-consuming and the measurement method is complex. We proposed a random three-frame object surface measurement Conventional phase shifting shadow moiré profilometry usually needs more phase shifting images to demodulate the measurement phase because of the nonlinear phase shifting. The data sampling process is time-consuming and the measurement method is complex. We proposed a random three-frame object surface measurement method based on the principal component analysis and the shadow moiré profilometry. The phase shift is introduced by translating grating perpendicular to its own plane. Given that the background of captured fringe patterns is a smooth signal, we firstly normalized the sampled fringe patterns. Then principal component analysis based phase shifting algorithm is used to estimate the phase. The proposed method is fast and can be implemented easily in many applications. We also did optical experiments to demonstrate the effectiveness of the proposed method by referring to the result of conventional five-step phase shifting shadow moiré. The results show that the difference of the measurement results is within ±5 μm..
Laser & Optoelectronics Progress
- Publication Date: Sep. 24, 2016
- Vol. 53, Issue 10, 100501 (2016)
Fiber Optics and Optical Communications
Propagation Properties of Partially Coherent Array Beams in Free Space Optics System
Ke Xizheng, and Zhang Ya
Based on the generalized Huygens-Fresnel principle and the modified von Karman spectrum model, the analytic expressions of the intensity distribution, the root mean square beam width and the power in the bucket of mutually-independent partially-coherent Gaussian-Shell model (GSM) array beams in the free space optics syBased on the generalized Huygens-Fresnel principle and the modified von Karman spectrum model, the analytic expressions of the intensity distribution, the root mean square beam width and the power in the bucket of mutually-independent partially-coherent Gaussian-Shell model (GSM) array beams in the free space optics system are derived when the beams propagate in the atmospheric turbulence. The self-coupling characteristics, the power in the bucket and the beam spreading are analyzed numerically under the influence of different factors. The results show that when the partially coherent GSM array beams propagate for a certain distance in the atmospheric turbulence, they will be synthesized into a flat-topped beam which then evolves to a Gaussian beam. Moreover, the self-coupling characteristics of the array beams in atmospheric turbulence are better than those in free space. The influence of turbulent outer scale on the intensity distribution and beam spreading is very small, and can be ignored. Compared with the partially coherent single GSM beam, the partially coherent GSM array beams have stronger anti-turbulence properties, which is beneficial to realizing long-distance communications..
Laser & Optoelectronics Progress
- Publication Date: Sep. 25, 2016
- Vol. 53, Issue 10, 100601 (2016)
High-Sensitivity Strain Sensor of Long Period Fiber Grating Based on Grooved Technology
Liu Yu, Li Yunmei, Lu Yongle, Zhou Fan, and Zhong Yi
Two kinds of long period fiber gratings (LPFGs) with different grooved depths are fabricated by means of the improved CO2 laser beam. The influence of the grooved structure of the fiber grating on the strain sensing characteristics is studied experimentally. The research results show that the stain concentration is occTwo kinds of long period fiber gratings (LPFGs) with different grooved depths are fabricated by means of the improved CO2 laser beam. The influence of the grooved structure of the fiber grating on the strain sensing characteristics is studied experimentally. The research results show that the stain concentration is occurred in the surface of the fiber grating because of the one-side periodical groove, and the grooved fiber grating slightly is bent to form corrugated structure, so the strain sensitivity response is greatly enhanced. Resonance wavelength of the transmission spectrum of the deeply grooved fiber can linearly driftes to -10.96 nm, the sensitivity can get to -19.37 pm/με and the measurement error is very small. The mesh modeling and static simulation of the grooved fiber grating are realized based on the finite element analysis software ANSYS, and then the strain distribution of the grooved structure section is obtained. The principal research and experimental testing demonstrate that the axial micro-bend deformation of the grooved LPFG increase with the increase of strain, so that the grooved fiber can trigger high-order cladding mode coupling, and improve strain sensitivity response..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 100602 (2016)
Fiber Bragg Grating Temperature Sensitization Sensor with Seawater Corrosion-Resistance
Gao Xiaodan, Qu Yapeng, and Wang Yao
A miniature fiber Bragg grating (FBG) temperature sensor with a galvanized sensitization copper film and a seawater corrosion-resistant carbon film is designed by the electroplating process and the magnetron sputtering. When the seawater temperature within the range of 0~50 ℃, the Bragg wavelength of the FBG temperaturA miniature fiber Bragg grating (FBG) temperature sensor with a galvanized sensitization copper film and a seawater corrosion-resistant carbon film is designed by the electroplating process and the magnetron sputtering. When the seawater temperature within the range of 0~50 ℃, the Bragg wavelength of the FBG temperature sensitization sensor is linear with the seawater temperature, and the linear coefficient is nearly 99.99%. The temperature sensitivity can be precisely controlled by the electroplating time and the electric current. The properties of temperature and the seawater corrosion-resistance of the three kinds of sensing probes, e.i., the probe with copper plating film, the probe with copper and carbon plating film, the probe with copper and silica plating film, are analyzed. The results show that the temperature sensitivity coefficient increases exponentially with the copper film thickness, and the copper film thickness increases linearly with the plating time. The carbon film with the diamond-like structure can inhibit the corrosion of the sensitization copper film in seawater..
Laser & Optoelectronics Progress
- Publication Date: Sep. 26, 2016
- Vol. 53, Issue 10, 100603 (2016)
Influence of High Order Sideband Suppression Ratio on Performance of All-Optical Wavelength Conversion System
Chang Haiyue, Lu Jia, Wang Yang, and Ma Jie
The influence of the high order sideband suppression ratio on the all-optical wavelength conversion system of the polarization multiplexing signal of parallel pumps based on carrier suppression is theoretically analyzed and simulated. According to the character of Bessel function curve, the optical sideband power with The influence of the high order sideband suppression ratio on the all-optical wavelength conversion system of the polarization multiplexing signal of parallel pumps based on carrier suppression is theoretically analyzed and simulated. According to the character of Bessel function curve, the optical sideband power with different frequencies is changed by controlling the radio frequency signal voltage and adjusting the modulation depth of the Mach-Zehnder modulator, then the parallel pump light with the same polarization direction, locked phase and different high order sidebands suppression ratios are obtained. The receiving bit error rate performance of the converting light under different sidebands suppression ratios is analyzed. The theoretical analysis and simulation results show that the bit error rate of the converted light on the x and y polarization directions can achieve 10-10 by controlling the modulation depth of the modulator in the range of (1.7,2.0), and the parallel pump light with the sidebands suppression ratio in the range of (7 dB,18 dB) is got correspondingly. The signal can be received by direct-detection without crosstalk. So there is no need to filter out the vestigial sidebands by using filter. It not only reduces the complexity of the system but also saves the system cost..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 100605 (2016)
Quasi-Distributed High Temperature Sensor Based on Fiber Bragg Grating
Du Yong, Si Jinhai, Chen Tao, Li Sijia... and Hou Xun|Show fewer author(s)
According to the requirement of quasi-distributed high temperature sensor based on fiber Bragg grating (FBG), preparation method of the FBGs with different periods is studied by using the femtosecond laser phase mask combined with fiber pulling. Periods of the FBGs are controlled by changing the stress applied to the fAccording to the requirement of quasi-distributed high temperature sensor based on fiber Bragg grating (FBG), preparation method of the FBGs with different periods is studied by using the femtosecond laser phase mask combined with fiber pulling. Periods of the FBGs are controlled by changing the stress applied to the fiber during femtosecond laser irradiation, then the quasi-distributed high temperature sensor based on the FBGs with different Bragg wavelengths is obtained. Temperature response parameter of the FBG is demonstrated, and two points quasi-distributed temperature measurement is achieved. The quasi-distributed sensor system is consist of the FBG demodulation instrument and FBGs with different Bragg wavelengths. Measured results of the FBG spectra under different temperatures indicate that the Bragg wavelength of the FBG is shifted linearly as the temperature increases. Reflectivity of the FBG keeps at -10.2 dB after annealing for a long time at 800 ℃. This FBG sensor system can be applicable to sensing measurement within 800 ℃..
Laser & Optoelectronics Progress
- Publication Date: Sep. 08, 2016
- Vol. 53, Issue 10, 100606 (2016)
Experimental Analysis of Fiber Material Property Based on Terahertz Wave
Liao Xiaoling, Liu Yanlei, Liu Xiaohua, Wu Jincai... and Zhao Dan|Show fewer author(s)
Terahertz (THz) time-domain spectroscopy technology is utilized to inspect the carbon fiber and glass fiber material and the field emission scanning electron microscope is assisted to observe sample morphologies. The study results show that, when the vibration direction of THz wave is perpendicular to the fiber sample Terahertz (THz) time-domain spectroscopy technology is utilized to inspect the carbon fiber and glass fiber material and the field emission scanning electron microscope is assisted to observe sample morphologies. The study results show that, when the vibration direction of THz wave is perpendicular to the fiber sample direction, most signals can be acquired. The absorption coefficient slope of glass fiber is smaller than that of carbon fiber. Both the fiber diameter and fiber arrangement pattern have certain influences on the transmission capability of THz wave..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 100607 (2016)
Holography
Digital Holographic Imaging with Single Pixel Bucket Detector
Long Tao, Wang Yurong, Jiang Shan, Meng Xiangfeng, and Yang Xiulun
In order to solve the problem that the plane-array detectors have small size of target surface, low resolution and difficult to make in certain wavelengths, a digital holographic imaging method with single pixel bucket detector is proposed. In this scheme, an optically addressed spatial light modulator (OASLM) works asIn order to solve the problem that the plane-array detectors have small size of target surface, low resolution and difficult to make in certain wavelengths, a digital holographic imaging method with single pixel bucket detector is proposed. In this scheme, an optically addressed spatial light modulator (OASLM) works as a conversion device between the digital holography system and computational ghost imaging system. The hologram of object to be imaged is used as the writing light and written directly into the OASLM. The written hologram is readout and retrieved by using computational ghost imaging procedure, in which an electrically addressed spatial light modulator is utilized to produce a sequence of updateable, computer-generated, and independent reference matrix. And a single pixel bucket detector is used to collect the intensity of the readout beam. The associated operation of light intensity signal and reference matrix is conducted, the reconstructed hologram is obtained through calculating the phantom imaging algorithm. The reproductive image of the object is obtained using the digital holographic reconstruction algorithm. The feasibility of the proposed method is proved by theory analysis and simulation experiment..
Laser & Optoelectronics Progress
- Publication Date: Sep. 22, 2016
- Vol. 53, Issue 10, 100901 (2016)
Image Processing
Research on High Resolution Digital Refocusing of Light Field Imaging Based on Microlens Array
Zhao Qingqing, Zhang Tao, and Zheng Weibo
The pictures in different directions, locations and depths of focus are obtained using the method of computational imaging to satisfy the different requirements and to achieve the function of taking the picture before focusing the camera, and overcoming the drawbacks of mechanical focusing in traditional camera. HoweveThe pictures in different directions, locations and depths of focus are obtained using the method of computational imaging to satisfy the different requirements and to achieve the function of taking the picture before focusing the camera, and overcoming the drawbacks of mechanical focusing in traditional camera. However, its image quality is lower than the traditional camera because its resolution is restricted by the number of microlens. The high resolution digital autofocus method is proposed, that is extracting the sub aperture pictures firstly, and then doubling the resolution of every sub aperature pictures by the method of the combination of wavelet transformation and interpolation. So, the sub aperature picture array with high resolution can be formed. The refocus processing on this array by Fourier slice transformation is done, and the processed results show that the definition and resolution of the refocused images increase greatly..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 101001 (2016)
Comprehensive Evaluation of Optical Camouflage Effect Based on Hyperspectra
Guo Tong, Hua Wenshen, Liu Xun, Liu Xiaoguang, and Cui Zihao
To fully utilize abundant spectral and texture information in hyperspectra, a method to comprehensively evaluate the optical camouflage effect is proposed. The method combines the similarity of spectral curve shape, the spectral Euclid distance and the texture Euclid distance. The three features are quantified by the aTo fully utilize abundant spectral and texture information in hyperspectra, a method to comprehensively evaluate the optical camouflage effect is proposed. The method combines the similarity of spectral curve shape, the spectral Euclid distance and the texture Euclid distance. The three features are quantified by the absolute correlation degree, Euclid distance and gray level co-occurrence matrix, respectively. The spectral and the texture information are taken into consideration in terms of the shape measure and the distance measure to obtain a comprehensive measure. This method is rigorous in theory, and it is experimentally proved to be robust and avoid the uncertainty of single measure. It is instructive for camouflage material design and usage..
Laser & Optoelectronics Progress
- Publication Date: Sep. 24, 2016
- Vol. 53, Issue 10, 101002 (2016)
Imaging Systems
Effect of Scattering Medium on Multi-Wavelength Color Object Correlated Imaging
Zhou Cheng, Liu Bing, Huang Heyan, and Song Lijun
The relationship of the multi-wavelength color imaging and full spectrum white light imaging versus the scattering medium concentration is studied by utilizing the single-beam correlated imaging technology，and the image restoration of color target objects is realized under the condition of scattering medium in the optiThe relationship of the multi-wavelength color imaging and full spectrum white light imaging versus the scattering medium concentration is studied by utilizing the single-beam correlated imaging technology，and the image restoration of color target objects is realized under the condition of scattering medium in the optical path. Experimental results demonstrate that under the condition of 3000 sampling number the imaging quality decreases with the increase of the scattering medium concentration. When the scattering medium concentration increases to 6%, the visibility of the multi-wavelength color image decreases from 0.21 to 0.061 and the contrast-to-noise ratio decreases accordingly from 1.21 to 0.33. But for the full spectrum white light imaging, the scattering medium concentration has little effect. In the same case, the visibility and CNR are 0.20 and 1.061, respectively. The relationship between the scattering medium concentration and the imaging quality of the color object correlated imaging is discussed in detail, which is crucial to the practicality of the correlated imaging..
Laser & Optoelectronics Progress
- Publication Date: Sep. 23, 2016
- Vol. 53, Issue 10, 101102 (2016)
Instrumentation, Measurement and Metrology
Indoor Integrated Navigation Algorithm Based on Photoelectric Scanning and Strapdown Inertial Navigation System
Wang Jiao, Yang Linghui, Huang Zhe, Shi Shendong, and Huang Dong
One algorithm for integrated navigation based on photoelectric scanning and strapdown inertial navigation system (SINS) is proposed. Based on the actual measurement results, the time series analysis of wMPS dynamic measurement data is established, and it is proved that a first-order autoregressive process can be applieOne algorithm for integrated navigation based on photoelectric scanning and strapdown inertial navigation system (SINS) is proposed. Based on the actual measurement results, the time series analysis of wMPS dynamic measurement data is established, and it is proved that a first-order autoregressive process can be applied to model the wMPS dynamic measurement errors. Based on the SINS error model and the time series analysis result of the wMPS dynamic measurement data, the Kalman filtering model of indoor integrated navigation system is established, and the algorithm simulation experiment is conducted. The simulation results indicate that the integrated navigation system simultaneously possess the advantages of high data rate of SINS and high precision of wMPS. The whole performance of this system is significantly enhanced..
Laser & Optoelectronics Progress
- Publication Date: Sep. 21, 2016
- Vol. 53, Issue 10, 101201 (2016)
Optical Fiber Bragg Grating Temperature Monitoring Based on Volume Phase Grating Dispersion Demodulation
Wang Yan, Zhao Kai, and Liu Jiaping
A fiber grating temperature monitoring system based on the fiber Bragg grating analyzer (FBGA) demodulation module is constructed, and the temperature monitoring for the external environment is realized. The peak wavelength of the reflected light is obtained through the digital signal processing module in FBGA, and theA fiber grating temperature monitoring system based on the fiber Bragg grating analyzer (FBGA) demodulation module is constructed, and the temperature monitoring for the external environment is realized. The peak wavelength of the reflected light is obtained through the digital signal processing module in FBGA, and the fitting method is used to obtain the relationship between the peak wavelength and the temperature. LabVIEW is used to write the corresponding upper computer program. The measurement accuracy of the proposed measuring method is high. Compared with the constant temperature experiment, the temperature error of the proposed system is within ±0.5 ℃, the system response time is less than 0.5 s, and the temperature sensitivity of the system is about 0.1 ℃. When the confidence level is 95.40%, the repeatability index is within ±0.0210%..
Laser & Optoelectronics Progress
- Publication Date: Sep. 26, 2016
- Vol. 53, Issue 10, 101202 (2016)
Method of Fizeau Simultaneous Phase-Shifting Interferometry Based on Quarter-Wave Plate
Jiang Chao, Guo Renhui, Zhang Huiqin, Zhou Xiang... and Chen Lei|Show fewer author(s)
For the purpose of anti-vibration for interference measurement of flat surface, a method of simultaneous phase shifting interferometry is proposed in this paper, and the experimental device is set up. Based on Fizeau phase-shifting interferometer and using quarter-wave plate as reference mirror, the whole measurement sFor the purpose of anti-vibration for interference measurement of flat surface, a method of simultaneous phase shifting interferometry is proposed in this paper, and the experimental device is set up. Based on Fizeau phase-shifting interferometer and using quarter-wave plate as reference mirror, the whole measurement system acquires a pair of orthogonal polarized light. By using beam splitting of the chessboard phase grating, diffracted beams of (±1，±1) orders are selected by the aperture for the same ideal grating diffracting efficiency as measured beams. The four diffracted beams pass through a phase delay array and a polarizing plate to obtain four interference patterns with phase-shifting of π/2 respectively. According to the traditional four step phase shifting algorithm, the measured wave front is restored. The influence of light intensity distortion and phase shift error on the system measuring error is analyzed. It can simplify the structure of the system, reduce the system error, make installation the easier and the measurement more suitable for the plane, by comparing to the Twyman simultaneous phase shifting interferometry..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 101203 (2016)
Difference in Self-Absorption Effect Compensations Between Power-Spectral Method and Photometric Method for the Luminous Flux Measurements
Liu Xiangyuan, Zhang Suimeng, Xu Wenqing, Fan Chuanyu, and Wang Jin
Integrating spheres are often used to measure the total luminous flux of lamps by comparison methods, including power-spectral method and photometric method. Correction factors are introduced to compensate the loss of luminous flux due to self-absorption effect in the measurement process with the two methods. DifferencIntegrating spheres are often used to measure the total luminous flux of lamps by comparison methods, including power-spectral method and photometric method. Correction factors are introduced to compensate the loss of luminous flux due to self-absorption effect in the measurement process with the two methods. Difference in self-absorption effect compensation between the power-spectral method and the photometric method in luminous flux measurement is studied. According to the fundamental principle of luminous flux measurement, the expressions of modified luminous flux are obtained. Based on experimental data and theoretical analysis, influence of auxiliary lamps with different spectra on luminous flux results measured by the two methods is discussed. The results show that modified luminous flux is irrelevant to the relative power distribution of auxiliary lamps by the power-spectral method instead of that by the photometric method. Further results indicate that the modified luminous flux obtained by the power-spectral method remains same in spite of auxiliary lamps with different spectra, however, the modified value of luminous flux changes when the photometric method is used..
Laser & Optoelectronics Progress
- Publication Date: Sep. 23, 2016
- Vol. 53, Issue 10, 101204 (2016)
Lasers and Laser Optics
Research on Laser Processing Technology of Silicon Substrate AlGaInP LED
Xiao Heping, Chen Liang, Ma Xiangzhu, and Yang Kai
With semiconductor laser, a silicon substrate AlGaInP LED is prepared, and the effects of laser energy density, repetition rate, and processing speed of the platform on the processing results are studied. By means of electron microscope and other test tools, the structural characteristics of the surface and side morphoWith semiconductor laser, a silicon substrate AlGaInP LED is prepared, and the effects of laser energy density, repetition rate, and processing speed of the platform on the processing results are studied. By means of electron microscope and other test tools, the structural characteristics of the surface and side morphologies of silicon substrate AlGaInP LED chips are analyzed, and the superior processing parameters are obtained..
Laser & Optoelectronics Progress
- Publication Date: Sep. 19, 2016
- Vol. 53, Issue 10, 101401 (2016)
Research on Filtering Algorithm Based on Laser Ranging System
Wang Dan, Zhao Xin, Zou Yonggang, Ma Xiaohui... and Wang Weipeng|Show fewer author(s)
A nonlinear filtering algorithm based on the combination of Kalman filtering and minimum mean square error filtering is proposed for the pulsed semiconductor laser ranging system, and the echo signal of ranging system is filtered and analyzed. The results show that the accuracy can be improved to 2.1 m, and the error rA nonlinear filtering algorithm based on the combination of Kalman filtering and minimum mean square error filtering is proposed for the pulsed semiconductor laser ranging system, and the echo signal of ranging system is filtered and analyzed. The results show that the accuracy can be improved to 2.1 m, and the error reduces by 65.63% when using the proposed nonlinear filtering algorithm to deal with the experimental data..
Laser & Optoelectronics Progress
- Publication Date: Aug. 31, 2016
- Vol. 53, Issue 10, 101402 (2016)
Design of Lens Duct Coupling System in High Energy All-Solid-State Laser
Peng Chao, Liu Xuesheng, Yang Guanghui, Dong Jian... and Wang Zhiyong|Show fewer author(s)
Due to inhomogeneous spatial distribution and large divergence angle of the laser diode array (LDA), LDA is inconvenient for end-pumping solid-state lasers, and the output beam reshaping and coupling is required. A coupling system for end-pumping solid-state lasers is designed with Zemax. The system is composed of a faDue to inhomogeneous spatial distribution and large divergence angle of the laser diode array (LDA), LDA is inconvenient for end-pumping solid-state lasers, and the output beam reshaping and coupling is required. A coupling system for end-pumping solid-state lasers is designed with Zemax. The system is composed of a fast axis collimating lens and a lens duct. The relationship between the coupling efficiency and the characteristic parameters of the lens duct is studied. The optimal coupling system parameters are obtained by ray tracing. The final designed lens duct is 22 mm long, the input surface size is 12 mm (fast axis) ×9 mm (slow axis), the output surface size is 3.5 mm×3.5 mm, the radius of curvature is 14 mm, and the coupling efficiency can reach 90.7%. The beam divergence angle at 1 mm away from the lens duct is 0.38 mrad for fast axis and 0.02 mrad for slow axis. This system can make the pumping beam and the oscillating beam match well..
Laser & Optoelectronics Progress
- Publication Date: Sep. 24, 2016
- Vol. 53, Issue 10, 101404 (2016)
Study on the Laser Outside of the Field of View Disturbing the Space Camera
Shen Zhenmin, Shang Weidong, Tao Yuliang, and Yang Jukui
The off-axis laser disturbance on the camera is mainly caused by the laser diffraction and laser speckle interference. The models of the laser diffraction and the laser speckle interference are built respectively. The image of laser diffraction and laser speckle on the camera are analyzed under different parameters conThe off-axis laser disturbance on the camera is mainly caused by the laser diffraction and laser speckle interference. The models of the laser diffraction and the laser speckle interference are built respectively. The image of laser diffraction and laser speckle on the camera are analyzed under different parameters conditions, including the angle of incidence of laser beam, the caliber of lens, and the focal length of lens and F number. The effects of disturbing the camera by the laser diffraction and laser speckle interference are analyzed and compared at different parameters. The laser diffraction effect on the camera is significant when the laser beams are vertical incident to the space camera. The laser speckle interference effect becomes the leading role when the laser beams are oblique incident to the space camera..
Laser & Optoelectronics Progress
- Publication Date: Sep. 23, 2016
- Vol. 53, Issue 10, 101405 (2016)
Experimental Study of Tensile and Wear Resistance Properties of ZK60 Magnesium Alloy Treated by Laser Shock Peening
Wang Hao, Huang Yihui, Zhang Wenwu, Ru Haolei, and Wang Shengbo
With pulsed Nd:YAG laser, ZK60 magnesium alloy is treated by laser shock peening (LSP). Influences of laser energy density, single-/double-sided LSP treatment, presence or absence of protective coating, and other process parameters on the mechanical property of ZK60 magnesium alloy are analyzed. Meanwhile, the wear resWith pulsed Nd:YAG laser, ZK60 magnesium alloy is treated by laser shock peening (LSP). Influences of laser energy density, single-/double-sided LSP treatment, presence or absence of protective coating, and other process parameters on the mechanical property of ZK60 magnesium alloy are analyzed. Meanwhile, the wear resistance property of ZK60 magnesium alloy before or after LSP is tested. The experimental results show that LSP can improve the mechanical and wear resistance properties of ZK60 magnesium alloy, the reinforcing effect for high power density is better than that for low power density, there is no obvious difference between the single-sided and double-sided LSP treatments, and with the presence of protective coating, the honeycomb ablation layer occurring on the material surface can be avoided..
Laser & Optoelectronics Progress
- Publication Date: Sep. 19, 2016
- Vol. 53, Issue 10, 101406 (2016)
Experimental System for Measuring Carrier Mobility Based on Photo-CELIVZhang PengGong Erdong
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An experimental system for measuring carrier mobility based on Photo-CELIV is built. With a pulsed Nd3+YAG laser as an induction light source and under the operating frequency ranging from 1 Hz to 20 Hz, the whole system has an output laser with a wavelength of 532 nm, a pulse width of 10 ns, the tunable energy rangingAn experimental system for measuring carrier mobility based on Photo-CELIV is built. With a pulsed Nd3+YAG laser as an induction light source and under the operating frequency ranging from 1 Hz to 20 Hz, the whole system has an output laser with a wavelength of 532 nm, a pulse width of 10 ns, the tunable energy ranging from 0.1 mJ to 1 mJ, and a spot diameter being less than 2 mm. The laser energy instability after continuous work over 5 h is ±8%. The study here provides certain reference for the measurement of carrier mobility in semiconductor materials..
Laser & Optoelectronics Progress
- Publication Date: Sep. 19, 2016
- Vol. 53, Issue 10, 101407 (2016)
Fabrication of Super-Hydrophobic Aluminum Surface by Picosecond Laser
Liu Dun, Wu Yigang, Hu Yongtao, Wu Ying... and Bennett Peter|Show fewer author(s)
The super-hydrophobic aluminum surface is prepared by picosecond laser, and the effect of number of laser pulses on the surface morphology and wettability of samples is investigated. With the increment of number of pulse, the surface microstructure of samples transforms gradually from regular nano-stripped one to microThe super-hydrophobic aluminum surface is prepared by picosecond laser, and the effect of number of laser pulses on the surface morphology and wettability of samples is investigated. With the increment of number of pulse, the surface microstructure of samples transforms gradually from regular nano-stripped one to micro-nano-hybrid one, and the surface roughness first increases and then decreases. When the number of pulses is 177, the roughness is the maximum (3.855 μm). After laser processing, the surface wettability of samples first appears super-hydrophilic. But after a process with a heat preservation at 100 ℃ of 24 h, it becomes hydrophobic or even super-hydrophobic. The surface wettability transformation of samples is the joint action result of both the surface morphology and the chemical elements..
Laser & Optoelectronics Progress
- Publication Date: Sep. 27, 2016
- Vol. 53, Issue 10, 101408 (2016)
Research on Forming Process of Flake Graphite Powder by Selective Laser Sintering
Wu Haihua, Li Tengfei, Xiao Linnan, and Xiong Pan
The selective laser sintering technology is applied to the formation of phenolic resin/flake graphite hybrid powder by using the phenolic resin powder as the binder and the functional devices with excellent properties such as high conductivity, high thermal conductivity, and so on are produced. The forming mechanism ofThe selective laser sintering technology is applied to the formation of phenolic resin/flake graphite hybrid powder by using the phenolic resin powder as the binder and the functional devices with excellent properties such as high conductivity, high thermal conductivity, and so on are produced. The forming mechanism of such hybrid powder via laser sintering is clarified. The finite element method is used to analyze the variation of the heat affected zone during the laser sintering process, and a set of reasonable process parameters for sintering are determined. Based on the combination of the aforementioned parameters, the rapid preparation of porous graphite skeleton is realized, which verifies the feasibility of the above-mentioned process..
Laser & Optoelectronics Progress
- Publication Date: Sep. 19, 2016
- Vol. 53, Issue 10, 101409 (2016)
Continuous-Wave Passively Mode-Locked Nd:CGA Lasers
He Kunna, Liu Jiaxing, Xu Xiaodong, Wang Zhaohua... and Wei Zhiyi|Show fewer author(s)
The continuous wave (CW) and passive mode-locking features of a diode-pumped Nd:CGA laser are experimentally demonstrated with a typical X-type cavity. Under the CW operation, different output couplers (OCs) were used to optimize the CW output power of the Nd:CGA laser. With the OC of 20% transmission, the maximum CW oThe continuous wave (CW) and passive mode-locking features of a diode-pumped Nd:CGA laser are experimentally demonstrated with a typical X-type cavity. Under the CW operation, different output couplers (OCs) were used to optimize the CW output power of the Nd:CGA laser. With the OC of 20% transmission, the maximum CW output power of 1.8 W is achieved and the slope efficiency is 30.8% at the central wavelength of 1079 nm. By employing a semiconductor saturable absorber mirror for passive mode-locking, pulses as short as 2.7 ps with 177 MHz repetition rate are achieved for OC with transmission of 1.6%. The maximum average output power of 524 mW is obtained under a pump power of 6.9 W. The optical-to-optical conversion efficiency and the slope efficiency are 7.6% and 8.0%, respectively..
Laser & Optoelectronics Progress
- Publication Date: Sep. 21, 2016
- Vol. 53, Issue 10, 101410 (2016)
Machine Vision
Kernelized Correlation Filters Object Tracking Method with Multi-Scale Estimation
Pan Zhenfu, and Zhu Yongli
Visual object tracking is widely used in various fields such as video intelligent monitoring and visual navigation of robot. Aiming at the problem that traditional kernelized correlation filter (KCF) tracking method is lack of target scale estimation, and performs poor in video sequence whose target scale changes obserVisual object tracking is widely used in various fields such as video intelligent monitoring and visual navigation of robot. Aiming at the problem that traditional kernelized correlation filter (KCF) tracking method is lack of target scale estimation, and performs poor in video sequence whose target scale changes observably, a multi-scale estimation modified method is proposed. This method uses reference for discriminative spacial scale tracker (DSST) to make scale estimation by adopting the scale pyramid correlation filter. The gray image pyramid is mapped to a one dimensional feature vector, and then this vector is used as input of scale correlation filter. The target scale is estimated from the highest response values. This modified method is tested on benchmark data set, and it is compared with the other current visual tracking methods. The results verify the high efficiency of the proposed algorithm. The proposed algorithm has strong adaptability under complex conditions, such as object scale change, illumination variation, posture change, partial sheltering, rotating and rapid movement..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 101501 (2016)
Vehicle Type Recognition Based on Combining Local Binary Pattern and Hu Matrix Feature
Li Chengfei, and Chen Xinhua
The vehicle type recognition algorithm which combines local binary pattern (LBP) and Hu matrix feature is proposed. LBP feature can describe the local texture of vehicle. Hu matrix features are global features, and can reflect the shape contour information of the vehicle. The recognition algorithm of the fusion of LBP The vehicle type recognition algorithm which combines local binary pattern (LBP) and Hu matrix feature is proposed. LBP feature can describe the local texture of vehicle. Hu matrix features are global features, and can reflect the shape contour information of the vehicle. The recognition algorithm of the fusion of LBP and Hu matrix can describe the vehicle type characteristics. The vehicle recognition system is constructed by using the proposed fusion feature extraction method and the support vector machine classifier. The fusion algorithm achieves better performance than the single feature algorithm, and improves the vehicles recognition rate..
Laser & Optoelectronics Progress
- Publication Date: Sep. 23, 2016
- Vol. 53, Issue 10, 101503 (2016)
Effects and Correction of Camera Shaking in Stereo Measurement
Wu Linhong, Liu Jinbo, Zhang Xiaohu, Wang Gang, and Sun Cong
The measurement error influenced by the camera tiny shaking including translation, rotation and the combination in the stereo measurement are analyzed. The correction method of camera shaking based on the theory of photogrammetry is proposed, using control points in scene and the measurement error by calculating the caThe measurement error influenced by the camera tiny shaking including translation, rotation and the combination in the stereo measurement are analyzed. The correction method of camera shaking based on the theory of photogrammetry is proposed, using control points in scene and the measurement error by calculating the camera pose with corrected pose estimation. Simulation results show that, with the tiny shaking, the camera translation makes the measurement errors increase linearly, while the rotation makes the errors grow quadratically. The re-projection error in the object space is less than 1 mm with short distance measurement and proper arrangement of four control points, and it gradually falls below 0.55 mm with the increase of control points number. Simulation experiment verifies the reliability of the correction method, and this method can be used in stereo measurement on an unstable platform to reduce the effect of camera shake..
Laser & Optoelectronics Progress
- Publication Date: Sep. 23, 2016
- Vol. 53, Issue 10, 101504 (2016)
Optical Design and Fabrication
Optical System Design of Object-Telecentric Dual Finger Fingerprint Scanner
Zhou Lu, Chi Yaodan, and Guo Liang
Traditional optical single finger fingerprint scanner has some problems, such as small scanning window, limited extracting feature point, serious trapezoidal distortion of fingerprint original image, which directly affect the accuracy of fingerprint identification. To acquire a fingerprint scanner system with high resoTraditional optical single finger fingerprint scanner has some problems, such as small scanning window, limited extracting feature point, serious trapezoidal distortion of fingerprint original image, which directly affect the accuracy of fingerprint identification. To acquire a fingerprint scanner system with high resolution and high identification accuracy, in this paper, the dual finger fingerprint scanner with object-telecentric optical system is designed, which enlarges the size of scanning window and corrects the angle of the trapezoidal distortion. An object-telecentric optical system model is established by Zemax optical design software. By adjusting the suitable merit function and balancing all kinds of aberration, high imaging quality is acquired. The size of effective scanning window is 40.64 mm × 38.10 m. The modulation transfer function values of the center and edge view field of image are all bigger than 0.4 with corresponding characteristic frequency at 167 lp/mm, the optical distortion is less than 1%, and the system resolution is up to 500 dpi..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 102201 (2016)
Optical Design of Ultrashort Pulses Compressor Based on Prism Pairs
Zhang Liuyang, Jin Haiyang, Qu Yuqiu, Pu Shaozhi... and Yang Ying|Show fewer author(s)
Aiming at the problem of pulses compression in a Tisapphire solid laser cavity, optical design software is employed to design the ultrashort pulses compressor with prism pairs, which can compensate group delay dispersion (GDD) can compress the ultrashort pulses. First, a model of pulses compressor with prism pairs is bAiming at the problem of pulses compression in a Tisapphire solid laser cavity, optical design software is employed to design the ultrashort pulses compressor with prism pairs, which can compensate group delay dispersion (GDD) can compress the ultrashort pulses. First, a model of pulses compressor with prism pairs is built by optical design software. And the linear relation between GDD and the distance of prism pairs are obtained by a macro which can compute GDD. Combined with GDD of a sapphire crystal, the compressor structure parameters match with GDD is obtained after optimization. When GDD of the pulses center wavelength are compensated, GDD of marginal wavelengths is reduced to 10 fs2 for a 100 fs pulse by using low-dispersion fused silica. Computation of GDD in an optical system using optical design software has the advantage of perceptual intuition, simpleness, low computational complexity..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 102202 (2016)
Physical Optics
Design of Super-Airy Beam Laser
Deng Xiangquan, Xu Shixiang, Wu Qingyang, and Zheng Guoliang
Compared with the traditional two-dimensional Airy beams, the super-Airy beams have such transmission characteristics as no diffraction, self-bending and self-healing, and their main lobes have advantages like much smaller size and more intensive energy. Therefore, the super-Airy beams have a broad application prospectCompared with the traditional two-dimensional Airy beams, the super-Airy beams have such transmission characteristics as no diffraction, self-bending and self-healing, and their main lobes have advantages like much smaller size and more intensive energy. Therefore, the super-Airy beams have a broad application prospect in the optical micro-particle manipulation. In order to make a compact equipment for generating super-Airy beams, we present a laser design proposal for outputting the super-Airy beams directly. In our design, the 1% neodymium-doped yttrium aluminum garnet rod is pumped by a laser diode which is used as the pump source. The diffraction grating on which the cubic phase information of the super-Airy beams is loaded is used as the output coupler, so that it can output the super-Airy beams directly in the direction of the first order diffraction. The numerical calculation results show that the threshold power of the laser is 1.4 W, and the output power will rise up to 678 mW when the pump power is 2 W..
Laser & Optoelectronics Progress
- Publication Date: Sep. 28, 2016
- Vol. 53, Issue 10, 102601 (2016)
Algorithmic Model of Temperature Compensation for Infrared Methane Sensors
Yang Zhen, and Liang Yongzhi
With the statistical theory used, an algorithmic model of temperature compensation based on the Gaussian process regression is established for infrared methane sensors. The model parameters are studied to fit the data and to minimize the fitting error. In the Matlab software platform, the model is trained with the BayeWith the statistical theory used, an algorithmic model of temperature compensation based on the Gaussian process regression is established for infrared methane sensors. The model parameters are studied to fit the data and to minimize the fitting error. In the Matlab software platform, the model is trained with the Bayesian algorithm and the numerical simulation of temperature compensation is performed. The simulation results show that the model has small error and high accuracy, and it can compensate the nonlinear fluctuation of sensor signal at different temperatures..
Laser & Optoelectronics Progress
- Publication Date: Sep. 21, 2016
- Vol. 53, Issue 10, 102602 (2016)
Properties of Singularity Beam Produced by Elliptical Gaussian Beams Through Spiral Phase Plate
Wang Hui, Ding Panfeng, and Pu jixiong
Based on modulation characteristics of spiral phase plate (SPP) and the paraxial beam transmission theory, the complex amplitude function of elliptical Gaussian beams through SPP is investigated, and intensity and phase distributions of the elliptical singularity beams with different topological charges during propagatBased on modulation characteristics of spiral phase plate (SPP) and the paraxial beam transmission theory, the complex amplitude function of elliptical Gaussian beams through SPP is investigated, and intensity and phase distributions of the elliptical singularity beams with different topological charges during propagation are studied. It is shown that the spot shape is changed comparing with the initial spot shape in the process of transmission with increasing of propagation distance after SPP. On the one hand, A certain amount deflection of high-order elliptical singularity beam appears, and the deflection direction is associated with the symbol of the topological charge. On the other hand, the high-order elliptical singularity beam splits in the dark nuclear area during propagation, and the number of singularities is equal to the topological charge of the original beam, which is different from the fist-order elliptical singularity beams..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 102603 (2016)
Remote Sensing and Sensors
Computing the Atmospheric Point Spread Function by Artificial Neural Networks
Wang Haidong, Ma Xiaoshan, Yang Zhen, and Li Ligang
Atmospheric point spread function (PSF) is an effective research and correction method for the adjacency effect of the optical remote sensing. Based on the atmospheric PSF acquired by Monte Carlo simulation, a two-layer feed-forward neural network which has enough hidden neurons with Sigmoid function and linear output Atmospheric point spread function (PSF) is an effective research and correction method for the adjacency effect of the optical remote sensing. Based on the atmospheric PSF acquired by Monte Carlo simulation, a two-layer feed-forward neural network which has enough hidden neurons with Sigmoid function and linear output neurons is designed and implemented. By means of Levenberg-Marquardt back-propagation algorithm, the relationship between the atmospheric PSF and its influence factors, such as atmosphere condition, spectral range and observation geometry is obtained. The results obtained show that our neural network can estimate the atmosphere PSF with 95% accuracy within relatively short time..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 102801 (2016)
Polarized Reflectance Characteristics of Vegetation Canopies Based on Polarization Reflection Model
Sun Zhongqiu, and Zhao Yunsheng
The polarized reflectance characteristics of different vegetation canopies are analyzed based on field and laboratory multi-angle polarization measurements and physical mechanism of polarized reflectance. The parameters of two polarized reflectance models are obtained respectively. The results show that the polarized rThe polarized reflectance characteristics of different vegetation canopies are analyzed based on field and laboratory multi-angle polarization measurements and physical mechanism of polarized reflectance. The parameters of two polarized reflectance models are obtained respectively. The results show that the polarized reflectance factors of vegetation canopies depend on the geometry of viewing and incident angle, the distribution of polarized reflectance of vegetation canopies is anisotropic and related to the structure of canopies. The polarized reflectance ratio reaches 0.095, much larger than the previous results. The polarized reflectance factors of vegetation canopies are effectively calculated by the polarized reflectance models, but there will be a large error when for flat-type and smooth blade canopies..
Laser & Optoelectronics Progress
- Publication Date: Sep. 23, 2016
- Vol. 53, Issue 10, 102802 (2016)
Reviews
Research Progress of Quantitatively Controlling Surface Residual Stress by Laser Shock Processing
Hua Guoran, Zhou Dongcheng, Cao Yupeng, Feng Aixin, and Chen Haotian
The newest research status of using laser shock processing (LSP) technology to quantitatively control the surface residual stress is elaborated, and the major problems in laser shock studies are specially discussed. It is pointed out that the laser interaction with materials, surface residual stress, and multi-scale chThe newest research status of using laser shock processing (LSP) technology to quantitatively control the surface residual stress is elaborated, and the major problems in laser shock studies are specially discussed. It is pointed out that the laser interaction with materials, surface residual stress, and multi-scale characterization in microstructure changes are the research hot spots in the field of LSP technology. Based on these, the prospect for the application of LSP technology in the quantitative control of surface residual stress as well as in heavy marine equipment manufacturing is conducted..
Laser & Optoelectronics Progress
- Publication Date: Sep. 22, 2016
- Vol. 53, Issue 10, 100001 (2016)
Advances in Attitude Inversion of Space Object Based on Photometric Data
Gou Ruixin, Du Xiaoping, and Liu Hao
For estimating attitude of unresolved targets, such as high earth orbit targets and micro-nano satellites, according to the analysis of correlational research at home and abroad, the main attitude estimation methods based on photometric data are comprehensively summarized. Then both the advantages and disadvantages of For estimating attitude of unresolved targets, such as high earth orbit targets and micro-nano satellites, according to the analysis of correlational research at home and abroad, the main attitude estimation methods based on photometric data are comprehensively summarized. Then both the advantages and disadvantages of these methods are analyzed. The attitude inversion method based on the nonlinear filter has high precision and near-realtime efficiency in the cases of steady state and maneuvering condition, and it is the dominant method in the future. On this basis, the key issuses of attitude inversion based on nonlinear filter are studied, such as shape inversion, selection of bidirectional reflectance distribution function models and its parameters, and the nonlinear filtering algorithm is discussed..
Laser & Optoelectronics Progress
- Publication Date: Sep. 20, 2016
- Vol. 53, Issue 10, 100002 (2016)
Thin Films
Spectral Ellipsometry of Dielectric/Metal/Dielectric Transparent Conductive Multi-Layer Films
Sun Yao, and Wang Hong
The optical and electrical properties of transparent conductive multi-layer films with dielectric/metal/dielectric structures are superior to those of single-layer transparent conductive oxide films or metal films, and the multi-layer films can be prepared at low temperature. The transparent conductive multi-layer ZnO/The optical and electrical properties of transparent conductive multi-layer films with dielectric/metal/dielectric structures are superior to those of single-layer transparent conductive oxide films or metal films, and the multi-layer films can be prepared at low temperature. The transparent conductive multi-layer ZnO/Ag/SiN film is prepared by magnetron sputtering at room temperature, and then the film is measured by variable-angle spectral ellipsometry. The refractive index and the extinction coefficient of every single layer are obtained by building physical models and fitting. The multi-layer model is established based on the single-layer models, and the measured and fitted ellipsometric spectra of multi-layers fit well. The results show that the carrier concentration in the Drude model of the functional Ag layer barely changes while mobility of the Ag layer varies under different flow rate ratios of O2 to Ar in reactive ZnO deposition. The mobility of the Ag layer becomes upmost when the flow rate ratio of O2 to Ar makes ZnO corresponding to the oxidization state. At this point, it is revealed by X-ray diffraction that the Ag layer has the best crystallization and preferred orientation..
Laser & Optoelectronics Progress
- Publication Date: Sep. 25, 2016
- Vol. 53, Issue 10, 103101 (2016)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20