Journals >Laser & Optoelectronics Progress
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2016
Volume: 53 Issue 1
36 Article(s)
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[in Chinese]
Advances in Dielectric Crystal Waveguides Produced by Direct Femtosecond Laser Writing
Jia Yuechen, and Chen Feng
Dielectric crystalline waveguides, with the combination of compact geometry of waveguides and astonishing properties of crystals, have developed as one of the unique platforms for versatile miniature and integrated photonic applications. Femtosecond-laser direct writing is one of the most efficient techniques for threeDielectric crystalline waveguides, with the combination of compact geometry of waveguides and astonishing properties of crystals, have developed as one of the unique platforms for versatile miniature and integrated photonic applications. Femtosecond-laser direct writing is one of the most efficient techniques for three-dimensional microfabrication of miniature photonic devices based on waveguiding structures in transparent optical materials. Focused on crystalline dielectric materials, the state-of-the-art in the fabrication, characterization and applications of femtosecond laser micromachined waveguiding structures in optical crystals and ceramics is reviewed. A brief outlook is presented by focusing on a few potential spotlights..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 10001 (2016)
Atmospheric Optics and Oceanic Optics
A Target Echo Extraction Method in Underwater Lidar System Based on Variable Forgetting Factor RLS Algorithm
Cheng Zao, Xia Min, Li Wei, Guo Wenping, Zeng Xianjiang, and Yang Kecheng
The restraining of water backscattering and increasing target resolution are the key technologies in underwater lidar detection. An adaptive filtering method of target echo based on recursive least- squares (RLS) algorithm is proposed. Through the feature analysis of underwater lidar detected signal, the forgetting facThe restraining of water backscattering and increasing target resolution are the key technologies in underwater lidar detection. An adaptive filtering method of target echo based on recursive least- squares (RLS) algorithm is proposed. Through the feature analysis of underwater lidar detected signal, the forgetting factor in traditional RLS algorithm is improved to distinguish the target echo and water backscattering signal. The improved forgetting factor can also adapt the echo amplitude changes in different target distances. To estimate the effect of the method, the underwater detection experiments are carried out in water basin under different target distances. The results show that the backscattering signals are suppressed and the target echo are extracted with high tracking and convergence speed by using the proposed variable forgetting factor RLS algorithm. Compared with the traditional methods, the resolution of the processed target echo signal is increased and the proposed method has great advantage in the weak target echo extraction. Finally, the impact of filter order on algorithm processing results is discussed..
Laser & Optoelectronics Progress
- Publication Date: Oct. 25, 2015
- Vol. 53, Issue 1, 10101 (2016)
Fault Tree Analysis on Reliability of Electronic Control System of Adaptive Optics
Gao Guoqing, and Zhou Luchun
The adaptive optics (AO) system involves many fields like optics, electronic control and so on, so it is necessary to improve the reliability of the electronic control system. The fault tree analysis (FTA) method introduced, and the key modules, such as the wavefront detection unit, wavefront processing unit, are analyThe adaptive optics (AO) system involves many fields like optics, electronic control and so on, so it is necessary to improve the reliability of the electronic control system. The fault tree analysis (FTA) method introduced, and the key modules, such as the wavefront detection unit, wavefront processing unit, are analyzed.A fault tree model of the system is established. The minimum cut sets of system are got through qualitative analysis. Similarly, the probability of failure of the system and the order of the importance of bottom incident are got through quantitative analysis. According to the result, the stability of system can be improved and the design of system can be optimized effectively..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 10102 (2016)
Fiber Optics and Optical Communications
Theoretical Model and Numerical Simulation of Simultaneous Measurement of Two Points Seawater Temperature
Wang Xin, Wang Jing, Zhou Hongzu, Yang Hongjuan, and Liao Yipeng
Seawater temperature is one of the basic parameters of ocean dynamics and it plays a key role in the interaction between the ocean and atmosphere. What′s more, seawater temperature is the most important parameter of all marine phenomenon research. In order to achieve the simultaneously measurement of seawater temperatuSeawater temperature is one of the basic parameters of ocean dynamics and it plays a key role in the interaction between the ocean and atmosphere. What′s more, seawater temperature is the most important parameter of all marine phenomenon research. In order to achieve the simultaneously measurement of seawater temperature at two points, a theoretical model of Sagnac ring with two high birefringence elliptical fibers is constructed. The transmission spectrum of the theoretical model is obtained by Jones matrix equation, and the relationship between the transmission spectra and the various parts of the structure parameters is also obtained. By the numerical simulation of the theoretical model with Matlab software, the impact of the transmission spectra is studied on the changes of two high birefringence elliptical fibers length proportion, deflection angle and temperature. The results show that the optimum length ratio of two high birefringence elliptical fibers is 1∶2. The polarization angles of the polarization controllers should be π/6 and π/3, respectively. The transmission spectra shift to shorter wavelength when the temperature increases. The formula is obtained to calculate the temperature changes of two high birefringence elliptical fibers by the wavelength shifts of spectral peaks. In addition, the length of single-mode fiber between the two high birefringence elliptical fibers has no effect on the shape of transmission spectrum and temperature sensitivity. The model can theoretically support and guide the practical application of high birefringence fiber Sagnac ring temperature sensor..
Laser & Optoelectronics Progress
- Publication Date: Nov. 03, 2015
- Vol. 53, Issue 1, 10601 (2016)
Error Analysis of Circular Polarization Maintaining Optical Fiber Gyroscope
Guo Yudong, and Ji Minning
Referring to the theoretical analysis method of the interference fiber optic gyroscope (FOG) based on linear polarization, the polarization error resulted from the circular polarization degree, coupling or reflex points, and misalignment of the butt-joint in a circular polarization maintaining optical fiber gyroscope iReferring to the theoretical analysis method of the interference fiber optic gyroscope (FOG) based on linear polarization, the polarization error resulted from the circular polarization degree, coupling or reflex points, and misalignment of the butt-joint in a circular polarization maintaining optical fiber gyroscope is analyzed. The result shows that the reflex points and the misalignment which easily cause polarization error in a linear polarization system do not make influence in a circular polarization FOG. As the coupling polarization error from coupling points changes exponentially with the loss coefficient, electing a high quality single circular polarization maintaining optical fiber is significant for reducing the polarization error..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 10602 (2016)
Novel Optical Power Splitter Based on Nonperiodic Subwavelength High-Index-Contrast Grating
Mao Min, Huang Yongqing, Fang Wenjing, Duan Xiaofeng, Liu Kai, and Ren Xiaomin
A novel optical power splitter (OPS) based on a nonperiodic subwavelength high-index-contrast grating (HCG) is proposed. The OPS can split the reflected light into two beams while maintaining a high reflectivity. In order to achieve a specific phase-shift distribution for the application mentioned above, a rigorous couA novel optical power splitter (OPS) based on a nonperiodic subwavelength high-index-contrast grating (HCG) is proposed. The OPS can split the reflected light into two beams while maintaining a high reflectivity. In order to achieve a specific phase-shift distribution for the application mentioned above, a rigorous coupled-wave analysis (RCWA) is used to calculate the reflectivity and phase shift of a periodic subwavelength HCG while changing the grating period and duty cycle to obtain the proper structural parameters of the HCG. The properties of the two-port OPS are numerically studied with a finite element method (FEM), which exhibits a 3.27 dB insertion loss and a wavelength varying from 1.50 to 1.60 μm. The presented OPS can be easily integrated with a semiconductor device..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 10603 (2016)
Capacity Calculation of Polymer Optical Fibers Communication Channels Based on Discrete Multitone Modulation
Miao Pu, and Wu Lenan
Considering the calculation of channel capacity of the step- index polymer optical fiber (SI- POF) communication system within the uncoded discrete multitone modulation (DMT), the intensity modulated direct detected (IM/DD) transmission scheme is mathematically modeled, and a novel uniform power loading technique is usConsidering the calculation of channel capacity of the step- index polymer optical fiber (SI- POF) communication system within the uncoded discrete multitone modulation (DMT), the intensity modulated direct detected (IM/DD) transmission scheme is mathematically modeled, and a novel uniform power loading technique is used to evaluate and calculate the maximum achievable date rate. With the help of Gaussian and first-order low pass filter channel model, the theoretical expressions for the optimal bandwidth and realistic capacity of SI-POF system are derived based on signal to noise ratio (SNR) gap. The numerical calculations with different equivalent SNRs and occupied bandwidths are compared and the real experimental transmissions with several fiber lengths are also implemented. The results demonstrate that the channel capacity is positively distributed to the equivalent SNR, yet inverse with the fiber lengths. Adopting the optimum bandwidth can effectively reduce the transmission rate loss. By the analysis, the accurate prediction of capacity is beneficial to the POF system designing..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 10604 (2016)
Design of Cascaded Erbium-Doped Fiber Amplifier Supporting Four Linearly Polarized Modes
Qin Zujun, Yuan Ming, Zhang Wentao, Ye Song, and Xiong Xianming
Erbium-doped fibers(EDFs) with multi-step ormulti-annular and multi-level doping profiles are difficult to be fabricated by modified chemical vapor deposition (MCVD). A cascaded amplifier, based on two EDFs with a central doping profile and an annular doping profile, is proposed to equalize modal gain among four linearErbium-doped fibers(EDFs) with multi-step ormulti-annular and multi-level doping profiles are difficult to be fabricated by modified chemical vapor deposition (MCVD). A cascaded amplifier, based on two EDFs with a central doping profile and an annular doping profile, is proposed to equalize modal gain among four linearly polarized modes. In the amplifier, the centered- and off-centered modes are mainly amplified in the central- and annulardoped EDFs, respectively. An improved genetic algorithm (GA) is employed to optimize the optimal fiber length and doping radius in each EDF. Results show that an average modal gain around 20 dB with differential modal gain (DMG) between signal modes being less than 3.5 dB is achieved for a pure LP11 pump beam..
Laser & Optoelectronics Progress
- Publication Date: Dec. 16, 2015
- Vol. 53, Issue 1, 10605 (2016)
Holography
Focal Plane Determination Based on Linear Weighting of Amplitude and Phase in Digital Holography
Yang Hong, Chen Hepeng, Liu Hai, Li Yang, Xu Guoqing, and Yang Yan
A new refocusing criterion taking advantage of both intensity and phase information of object wave front is applied to detect a focal plane. The wavefront of object includes amplitude and phase information and amplitude information is mainly employed to locate the focal plane on account of intensity of holograms is on A new refocusing criterion taking advantage of both intensity and phase information of object wave front is applied to detect a focal plane. The wavefront of object includes amplitude and phase information and amplitude information is mainly employed to locate the focal plane on account of intensity of holograms is on behalf of amplitude and easy to obtain. The study of the correlation coefficient (CC) method on intensity has been proved. Phase information is analyzed and employed in CC method and focusing distance obtained from the peak of CC curve. The difference between the two focal distance obtained by phase information and amplitude information is due to that there is a difference on amplitude and phase of wave front. The two distance obtained from CC curve of amplitude and phase is weighted based on linear weighting and a final focal plane is positioned. Experiments validate that it works effectively..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 10901 (2016)
Image Processing
Atmospheric Correction of Polarization Remote Sensing Image by Independent Component Analysis
Wang Jiejun, Yang Jie, Zhang Wentao, Wang Xinqiang, and Ye Song
when the sky is not in the field of view, the atmospheric correction algorithm based on independent component analysis is proposed. According to the independence of the high frequency information of the atmosphere and scene light, the polarization degree of atmosphere is estimated by independent component analysis and when the sky is not in the field of view, the atmospheric correction algorithm based on independent component analysis is proposed. According to the independence of the high frequency information of the atmosphere and scene light, the polarization degree of atmosphere is estimated by independent component analysis and mutual information optimization principle, and the airlight intensity at infinity is estimated with prior knowledge of the source image and atmospheric scattering physical model. Through experimental contrast analysis, the obtained atmospheric information results match the theoretical value, and the reasonability of atmospheric information estimation is verified. Meanwhile, for the influence of sensing image degradation caused by atmospheric medium, the linear polarization degree is fixed based on fuzzy rule, the airlight information is corrected, and the image quality is improved. The polarization remote sensing image reflects the terrain target characteristics more accurately after correction, and the ability of target detection and recognition is improved..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 11001 (2016)
An Improved IVT Algorithm for Object Tracking
Qiu Chunchun, Li Qingwu, Wang Tian, and Cheng Haisu
Aiming at the problem that the occlusion interference of unable tracking object effectively in incremental visual tracking (IVT) algorithm, an improved IVT target tracking algorithm is proposed. The problem of a single target appearance model in the IVT algorithm is solved and a hybrid representation method is adopted Aiming at the problem that the occlusion interference of unable tracking object effectively in incremental visual tracking (IVT) algorithm, an improved IVT target tracking algorithm is proposed. The problem of a single target appearance model in the IVT algorithm is solved and a hybrid representation method is adopted to represent the target appearance. If the target is not blocked, using the incremental principal component analysis and Gaussian observing noise to represent, otherwise using the continuous uniform probability distribution to represent. The energy minimization method is implemented for mixed model target tracking. Experimental results show that the proposed algorithm has the better ability of anti-occlusion interference during object tracking and it can realize real-time tracking of targets at the same time..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 11002 (2016)
Prediction of Rice Seed Germination Rate Based on Hyperspectral Image and Bag of Visual Words Model
Yu Shimiao, Lu Wei, Ding Dong, Hong Delin, and Dang Xiaojing
Germination rate is one of the most important quality parameters of rice seeds. In order to identify the quality of rice seeds rapidly, the hyperspectral imaging technology and the bag of visual words (BoVW) are combined to establish a grading model of rice seed germination rate. Three kinds of hybrid rice seeds, YLianGermination rate is one of the most important quality parameters of rice seeds. In order to identify the quality of rice seeds rapidly, the hyperspectral imaging technology and the bag of visual words (BoVW) are combined to establish a grading model of rice seed germination rate. Three kinds of hybrid rice seeds, YLiangyou302, Liangyou 108 and Nei5you8015 are selected to be aged artificially for 0, 1, 2, 3, 4 d under the condition of temperature of 40 ℃ and relative humidity of 100% , and 5 dynamic gradients are obtained. Hyperspectral images of 300 samples are randomly divided into a training set (200 samples) and a test set (100 samples). After imaging selection, the germination rate test is performed and the germination rate is calculated on the 14th day. Principal component analysis (PCA) is applied to select characteristic wavelengths from the full spectral band. Scale-invariant feature transform (SIFT) is used to extract the local features of each image. All local features are clustered by K-means algorithm to generate visual dictionary. The support vector machine (SVM) classification model of rice seed germination rate is established with the radial basis function (RBF), and the discrimination accuracy reaches 95.65%. The result suggests that it is feasible to predict germination rate of rice seeds by using hyperspectral imaging technology combined with BoVM model..
Laser & Optoelectronics Progress
- Publication Date: Nov. 13, 2015
- Vol. 53, Issue 1, 11003 (2016)
Imaging Systems
A Three-Dimensional Teeth Measurement System Based on Structured Light
Ou Pan, Wang Ting, and Li Ruixiang
A three-dimensional tooth profile measurement system based on projected structured light is presented. The system consists of a CCD (charge coupled device) camera and a DLP (digital light processing) 4500 projection module, combining Gray code and phase shifting fringe projection. A fast and accurate calibration methodA three-dimensional tooth profile measurement system based on projected structured light is presented. The system consists of a CCD (charge coupled device) camera and a DLP (digital light processing) 4500 projection module, combining Gray code and phase shifting fringe projection. A fast and accurate calibration method of camera and projector based on the calibration method proposed by Zhang Zhengyou is presented. Based on the system calibration, dental mold scanning experiments are performed to obtain a three-dimensional point cloud contour of dental wax. The experimental result shows that the system is capable of measuring the three-dimensional dental mold accurately, which provides a basis for the further application in the dental field..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 11102 (2016)
Instrumentation, Measurement and Metrology
Study on Measuring Technology of Surface Profile Based on Electronic Modulation Coherence
Dong Yuanli, and Wang Huilin
Measurement of surface profile can evaluate the smoothness of components. In order to implement measurement with high precision, it comes up with methods for surface-profile measurement, which are the electricdirect modulation for laser-beam frequency and the heterodyne coherence. Through the principle of differential Measurement of surface profile can evaluate the smoothness of components. In order to implement measurement with high precision, it comes up with methods for surface-profile measurement, which are the electricdirect modulation for laser-beam frequency and the heterodyne coherence. Through the principle of differential Doppler measurement, we can achieve the digital measurement and optical compensation. Through the technology of electric-direct modulation for laser-beam frequency, we can reduce the size of system and cost. Besides, the transmission by optical fiber has improved the ability of immunity. At the same time, it can improve the resolution by amplifying and tracking the signal measurement. By debugging the circuit, it provides a compensation for the error analysis. The experimental results show that the measurement uncertainty of the technology is less than 0.1%..
Laser & Optoelectronics Progress
- Publication Date: Nov. 13, 2015
- Vol. 53, Issue 1, 11201 (2016)
Design and Simulation on All Optical Real-Time Measurement of Transient Optical Signal
Zhang Zhuoning, Peng Qixian, Wang Jing, Wen Weifeng, and Tao Shixing
Real-time measurement of the transient optical signal provides invaluable information about the dynamic processes, such as optical data stream monitoring in all-optical network, velocity interferometry and performance evaluation of single optical pulse in physics of intense fields. An all optical system based on wide sReal-time measurement of the transient optical signal provides invaluable information about the dynamic processes, such as optical data stream monitoring in all-optical network, velocity interferometry and performance evaluation of single optical pulse in physics of intense fields. An all optical system based on wide spectral pump four wave mixing optical-optical sampling and time stretch is reported to measure the transient optical signal in real time. The proposed technique samples the optical signal with super-resolution, converts the single wavelength signal to wide spectral signal and stretches it using dispersive Fourier transformation. The process of four wave mixing and time stretch in theory are analyzed and its feasibility is verified..
Laser & Optoelectronics Progress
- Publication Date: Nov. 13, 2015
- Vol. 53, Issue 1, 11202 (2016)
Research on Relationship between Fringe Bandwidth and Frequency Spectrum of Wave-Front in Interferometry
Meng Xiaochen, Hao Qun, and Zhu Lianqing
Interferometry is one of the most effective methods in measurement science, and whether it is to increase the dynamic measurement range or to detect high frequency error of surface, it is limited to spatial bandwidth of detection. So the relationship between bandwidth of interference fringes and frequency spectrum of wInterferometry is one of the most effective methods in measurement science, and whether it is to increase the dynamic measurement range or to detect high frequency error of surface, it is limited to spatial bandwidth of detection. So the relationship between bandwidth of interference fringes and frequency spectrum of wave-front is becoming the focus of attention, and it is analyzed and simulated based on the Fourier optics theory. The results indicate that, the spatial spectrum of interference fringes intensity is the expansion of the frequency of wave-front distribution function. And the extent of the expansion is determined by the amplitude frequency product of the wavefront. With the increase of amplitude frequency product of the wave-front, the bandwidth of interference fringes will be greater. According to the CCD resolution, the total bandwidth of interference patterns can be determined, and then the maximum spatial frequency of wave-front can be obtained. That provides a theoretical quantitative basis for the spectral characteristics of the interference methods, the optimal allocation of bandwidth and the increase of dynamic measurement range..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 11203 (2016)
Lasers and Laser Optics
Research of Relationship Between Tensile Mechanical Properties of 45 Steel Laser-Hardened Surfaces and Fracture Fractal Dimension
Liu Anzhong, Zhang Su, Ding Kewei, and Lei Sheng
In this study, 45 steel tensile specimens were hardened by laser during a surface experiment that used different laser power strengths, whereas the ultimate tensile strength of each specimen was obtained during a tensile experiment. These experiments measured the depth and hardness of the hardening layers of the surfacIn this study, 45 steel tensile specimens were hardened by laser during a surface experiment that used different laser power strengths, whereas the ultimate tensile strength of each specimen was obtained during a tensile experiment. These experiments measured the depth and hardness of the hardening layers of the surface areas and logged fracture photographs using a scanning electric microscope (SEM) to perform the fractal analysis. The fracture showed fractal characteristics; therefore, fractal theory was applied to calculate the fractal dimension of the fracture. The conclusive research results show that the sample surface-hardening layer depths and surface hardness can be increased by increasing the laser power, and thus causes the gradual decrease of the ultimate tensile strength and the increase of the fracture fractal dimension. The ultimate tensile strength and the fracture fractal dimension can be characterized for this material type..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 11401 (2016)
YAG Laser Polishing of 38CrMoAl Surface
Na Ran, and Chen Tao
Laser polishing is a special processing technology with prospect of application, particularly used for processing small size parts with high hardness which can′t be achieved by conventional methods. 38CrMoAl has much superiority including high surface hardness, high fatigue strength and good resistance to overheating rLaser polishing is a special processing technology with prospect of application, particularly used for processing small size parts with high hardness which can′t be achieved by conventional methods. 38CrMoAl has much superiority including high surface hardness, high fatigue strength and good resistance to overheating resistance. And it is widely used in mechanical machining, such as piston bolt and lathe spindles. 38CrMoAl can be polished by laser in a more efficient and environmental way. 38CrMoAl is micro-polished by YAG laser (1064 nm). Surface roughness of 38CrMoAl steel is analyzed by a three-dimensional topography instrument. Based on the surface morphology characteristics before and after polishing, the better processing parameters of the voltage at 790 V, pulse duration at 0.17 ms and the polishing position above the laser focal plane 3 mm are obtained. By using the micro-polishing method, the surface roughness of the metal can be decreased from 142.02 nm to 79.10 nm which have fallen by 44.3%..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 11402 (2016)
Numerical Analysis for Dynamical Output in Free-Running Multi-Longitudinal Mode Erbium Doped Fiber Laser
Tang Kai, Wang Junjie, Ma Mingxiang, Xu Pan, and Hu Zhengliang
Erbium doped fiber laser (EDFL) is divided into multi- longitudinal mode (MLM) laser and singlelongitudinal mode (SLM) laser according to the frequency domain. The multi-longitudinal mode laser is hard to understand in the field of optical complex systems. Actually, fiber lasers belong to a type of optical complex systErbium doped fiber laser (EDFL) is divided into multi- longitudinal mode (MLM) laser and singlelongitudinal mode (SLM) laser according to the frequency domain. The multi-longitudinal mode laser is hard to understand in the field of optical complex systems. Actually, fiber lasers belong to a type of optical complex system with large degree of freedom, hundreds and thousands of longitudinal modes can typically coexist, exhibiting such nonlinear mode dynamics as complex mode hopping and high-dimensional chaos. However, most of the theoretical models and experimental tools for analyzing fiber lasers dynamics only focus on the collective behavior of dense longitudinal modes, omitting the dynamics individual modes, frequency-domain dynamic model for multi-mode fiber lasers is established, in which the quenching effect in ion pairs and the cross coupling mechanism among modes are considered. The multi-mode laser models can effectively describe the individual behavior and clustering behavior of a large number of modes, and reproduce theoretically the multi-mode dynamics of high-dimensional dynamical system in frequency domain..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 11403 (2016)
Measurement and Analysis of Junction Temperature of Semiconductor Laser Devices
Yang Yang, Yu Guolei, Li Peixu, Xia Wei, and Xu Xiangang
Junction temperature/thermal- resistance is reflected in the comprehensive cooling capacity of laser devices, which is closely related to the sintering quality of the solder layer. The operating junction temperatures of laser devices have been detected by the forward-voltage and wavelength-shift methods. The distributiJunction temperature/thermal- resistance is reflected in the comprehensive cooling capacity of laser devices, which is closely related to the sintering quality of the solder layer. The operating junction temperatures of laser devices have been detected by the forward-voltage and wavelength-shift methods. The distribution of voids in the solder layer have been analyzed using a scanning acoustic microscope. The results verify the feasibility of junction temperature measurement, and confirm the relation between the junction temperature and the sintering quality of laser chips. These results will pave the way for the development of semiconductor lasers and the filtering of laser devices..
Laser & Optoelectronics Progress
- Publication Date: Dec. 18, 2015
- Vol. 53, Issue 1, 11404 (2016)
Materials
Transfer Matrix Method of One-Dimensional Photonic Crystal Composed of Gyromagnetic Materials
Ma Rongkun, Wang Jijun, and Fang Yuntuan
In order to study the transmission properties of one-dimensional photonic crystal based on gyromagnetic materials, we propose a transfer matrix method. The transfer matrix method is based on the Maxwell′s equations, the permeability tensor and boundary conditions of electromagnetic field. All the equations are taken noIn order to study the transmission properties of one-dimensional photonic crystal based on gyromagnetic materials, we propose a transfer matrix method. The transfer matrix method is based on the Maxwell′s equations, the permeability tensor and boundary conditions of electromagnetic field. All the equations are taken no any approximation and suitable to any structure of one-dimensional photonic crystalcomposed of gyromagnetic materials..
Laser & Optoelectronics Progress
- Publication Date: Dec. 18, 2015
- Vol. 53, Issue 1, 11601 (2016)
Medical Optics and Biotechnology
Fluorescence Molecular Tomography via Greedy Method Combinedwith Region-Shrinking Strategy
Dong Fang, Hou Yuqing, Yu Jingjing, Guo Hongbo, and He Xiaowei
To reduce the ill- posedness of reconstruction for fluorescence molecular tomography (FMT), a reconstruction method combining adaptively iterative- shrinking permissible region strategy with subsection orthogonal matching pursuit algorithm is inspired by compressive sensing theory. The region of mesh nodes with higher To reduce the ill- posedness of reconstruction for fluorescence molecular tomography (FMT), a reconstruction method combining adaptively iterative- shrinking permissible region strategy with subsection orthogonal matching pursuit algorithm is inspired by compressive sensing theory. The region of mesh nodes with higher fluorescent yield is chosen to iteratively shrink permissible region and make the objective function have a global optimal solution. In simulation experiments on digital mouse model, reconstruction results for single target and double targets demonstrate that greedy algorithm combining with shrink region strategy can not only significantly improve localization accuracy of fluorescent target and quantitative distribution of fluorescent yield, but also reduce dependence of algorithm on parameters choice. Physical simulation experiment further validates feasibility and stability of the proposed method in practical FMT applications..
Laser & Optoelectronics Progress
- Publication Date: Dec. 18, 2016
- Vol. 53, Issue 1, 11701 (2016)
Nonlinear Optics
Optical Bistability of Sinc Function Photonic Crystal with Nonlinear Microcavity
Wang Yun, Feng Guoqiang, Liu Dan, Li Jianming, Ji Zijuan, Xiao Ming, and Xiao Fei
The nonlinear transfer matrix method is used to study the optical bistable characteristics of Sinc function photonic crystal with nonlinear micro cavity. The results show that the field strength in the nonlinear microcavity and bistable thresholds are different with the increase of number of cycles or the change of theThe nonlinear transfer matrix method is used to study the optical bistable characteristics of Sinc function photonic crystal with nonlinear micro cavity. The results show that the field strength in the nonlinear microcavity and bistable thresholds are different with the increase of number of cycles or the change of the position of the nonlinear micro cavity. The field strength decreases in the nonlinear microcavity and the bistable threshold increases with the increase of linear refractive index of the nonlinear microcavity..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 11901 (2016)
Analysis of the Ultrafast Recovery Process of Output Gain of Semiconductor Optical Amplifier with the Effect of Ultrashort Pump Pulse
Wang Dan, and Yu Zhenhong
The semiconductor optical amplifier (SOA) is simulated by the transmission equation and carrier rate equation of ultrafast nonlinear effects. The effects of carrier density pulsation (CDP), carrier heating (CH) and spectral burning hole (SHB) on SOA output gain and phase are studied respectively. The input pulse peak pThe semiconductor optical amplifier (SOA) is simulated by the transmission equation and carrier rate equation of ultrafast nonlinear effects. The effects of carrier density pulsation (CDP), carrier heating (CH) and spectral burning hole (SHB) on SOA output gain and phase are studied respectively. The input pulse peak power and the relaxation time of SOA are changed to simulate the CH gain curve. The result shows that in the ultrafast recovery process, the CH contributes more to the saturated than the SHB effect; the CDP effect produces the slow recovery process. The CDP effect is the main reason for the nonlinear phase shift. The effect of SHB on the phase shift of the probe can be ignored. The contribution of CH to the phase shift can produce about 0.8 rad. The intensity of CH can affect the degree of gain saturation and phase shift, but can′t shorten the ultrafast recovery time. Input pulse energy can change the degree of saturation of the CH gain, and with shorter relaxation time, the peak time of CH effect and the gain of SOA ultrafast recovery time decrease gradually..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 11902 (2016)
Optical Design and Fabrication
Free-Form Reflector Design for Muti-Direction Collimated Beam
Qian Wei, and Yang Bo
In the field of geodesy, it is common that engineers need to produce 360° circular collimated beam. Now, the scheme is collimating beam from semiconductor laser firstly. Then, projecting the collimated beam to a cone with a inclination of 45° and 360° circular collimated beam comes out. To solve existingIn the field of geodesy, it is common that engineers need to produce 360° circular collimated beam. Now, the scheme is collimating beam from semiconductor laser firstly. Then, projecting the collimated beam to a cone with a inclination of 45° and 360° circular collimated beam comes out. To solve existing problems such as complex structure, inconvenient installation and so on, a design of free-form reflector is proposed to make the whole optical system consist of semiconductor laser and reflector only. The first step is calculating discrete coordinates of freeform by establishing a differential equation in the case of assuming the source to a point source. Then fitting to a freeform surface with the discrete coordinates as above. At last, carrying out a optimization design in the software according to the actual size of source. Then the free-form surface will be obtained with the discrete coordinates as above. Finally, lighttools is used to optimize the optical system according to actual size of light source. The simulation reveals that semiconductor laser with 20° divergence, 50 mm radiusand 30 mm focus can obtain uniform beam of 30 mm width 10 m away..
Laser & Optoelectronics Progress
- Publication Date: Dec. 18, 2015
- Vol. 53, Issue 1, 12201 (2016)
Design of Optical System of Star Sensor with Wide Spectrum and Lager Relative Aperture
Han Long, Fu Qiang, Wang Chao, Zhang Yalin, Ma Wanzhuo, and Zhan Juntong
Star sensor is a kind of instruments which is used in measuring the spacecraft attitude with its highprecision. It mainly consists of three parts: an optical system, an image sensor circuit and the control of data processing circuit, of which the optical system is the core part of in imaging forming system. In this papStar sensor is a kind of instruments which is used in measuring the spacecraft attitude with its highprecision. It mainly consists of three parts: an optical system, an image sensor circuit and the control of data processing circuit, of which the optical system is the core part of in imaging forming system. In this paper, the optical star sensor system of large relative aperture, lager view, broad spectrum is designed. Through the improvements of the basic structure symmetric double Gauss, a kind of optical structures of optimization process with perfect imaging quality is realized on the stage of Zemax software. The system has a compact structure with its properties: 60 mm in focal length, F number of 1.5, field of view of 20°, and the range of working wavelength is 0.48~0.68 μm, and the ratio of length and focal length is 1.81. The structure is compact and it achieves some special requirements aberration. The end result of this system is to provide reference data for star tracker optical system design..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 12202 (2016)
An Alignment Method of Ultraviolet Lunar Sensor Based on Lens Centering
Han Juan, Chen Jianjun, Li Zhiyong, Li Xiaoyan, and Duan Jiayou
Ultraviolet lunar sensor, a part of CE lunar orbiting satellite, is a wide-field of view optical image sensor that references to the attitude of the moon. In order to ensure high coaxiality and symmetry of both annular and central fields, high coaxiality machining of the flange hole (central hole) for the octahedral pyUltraviolet lunar sensor, a part of CE lunar orbiting satellite, is a wide-field of view optical image sensor that references to the attitude of the moon. In order to ensure high coaxiality and symmetry of both annular and central fields, high coaxiality machining of the flange hole (central hole) for the octahedral pyramid mirror of the Ultraviolet lunar sensor is needed. Furthermore, high coaxiality assembly of the octahedral pyramid mirror and the objective lens are needed. The conventional method achieves the goal by changing washer thickness. It has obvious disadvantages such as alignment iteratively and lower precision. This paper presents a high-precision lens centering method for octahedral pyramid mirror. This method can find mean square neutral surface quickly and accurately, and realize precision machining of the flange hole (central hole). After the lens centering of the objective lens, the high coaxiality assembly of the octahedral pyramid mirror and the objective lens can be achieved. Experimental results demonstrate that the reflection image error of octahedral pyramid is 17.3″, it′s better than expected value 30″, and the coaxiality of flange hole and the end face runout are less than 0.005 mm The symmetry for the field of view of the octahedral pyramid relative to the center field of view of the objective len reaches 0.01 mm. This alignment of sensor has got verified successfully at CE-1 spacecraft′s space mission..
Laser & Optoelectronics Progress
- Publication Date: Dec. 18, 2015
- Vol. 53, Issue 1, 12203 (2016)
Optical Devices
Tunable Plasmonically Induced Transparency with Unsymmetrical Resonators
Sun Lin, Wang Xiaosai, Liang Xiuye, Liu Cheng, and Wang Jicheng
The tunable plasmonic-induced transparency (PIT) is proposed numerically in the plasmonic system composed of dual unsymmetrical resonators shaped metal-insulator-metal (MIM) waveguide. The specific filtering effects are realized by changing the length of the groove and dielectric constant. The phenomena of the plasmoniThe tunable plasmonic-induced transparency (PIT) is proposed numerically in the plasmonic system composed of dual unsymmetrical resonators shaped metal-insulator-metal (MIM) waveguide. The specific filtering effects are realized by changing the length of the groove and dielectric constant. The phenomena of the plasmonicinduced transparency caused by the surface plasmonic resonance in the waveguide are analyzed according to the electric field distributions. The finite element method (FEM) method is conducted to verify numerical simulation. The structure is applied widely in optical communication, integrated optics, and lithography..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 12302 (2016)
Study of Repetition-Rate Electro-Optic Switch Based on Transparent Conductive Films
Zhuang Lingping, Zhang Xiongjun, Zhang Jun, Wu Dengsheng, and Tian Xiaolin
Transparent conductive films (TCFs) electrode electro-optic switch is an ideal switch device for high average power, which can achieve high thermal management efficiency by reasonable design. A model based on the schematic diagram of TCFs electro-optic switch is proposed. The switch′s time characteristics and thermal eTransparent conductive films (TCFs) electrode electro-optic switch is an ideal switch device for high average power, which can achieve high thermal management efficiency by reasonable design. A model based on the schematic diagram of TCFs electro-optic switch is proposed. The switch′s time characteristics and thermal effects with average power loaded on the electro-optic are simulated by numerical modeling. The results show that the switch′s rise time can meet the requirements of the nominal time. The depolarization loss caused by temperature rise has small effect on the performance of the switch. The design of TCFs electro-optic switch for high average power can be applied to high average power laser system at high repitition-rate..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 12303 (2016)
Influence of Double Magnetic Lenses on Performance of Pulse-Dilation Framing Tube
Bai Yanli, Long Jinghua, Cai Houzhi, Liao Yubo, Lei Yunfei, and Liu Jinyuan
The pulse-dilation framing tube using the double magnetic lenses is designed and the performance of spatial resolution is simulated and measured. The spatial resolution of tube is measured through the 2# plate. The spatial resolution at the off-axis position is tested through a large cathode. The measurement results shThe pulse-dilation framing tube using the double magnetic lenses is designed and the performance of spatial resolution is simulated and measured. The spatial resolution of tube is measured through the 2# plate. The spatial resolution at the off-axis position is tested through a large cathode. The measurement results show that the spatial resolution of tube is 74 μm, and the 30 mm off-axis position on the cathode is resolved while the image is demagnified 1 times. The spatial resolution and the spatial resolving power at the off-axis position are better than the tube using the single magnetic lens. Therefore, the spatial resolving performance of pulse-dilation framing tube is improved by the double magnetic lenses..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 13201 (2016)
Reviews
Atomic and Molecular Experiments Progress in Free-Electron Laser Field
Feng He, Zhang Yizhu, and Jiang Yuhai
The free-electron lasers (FELs), a rapid developing technology as a new generation of advanced radiation sources in the last decade, provide ultra-fast, ultra-intense, ultra-short wavelength laser pulses, becoming a robust metrology to explore the forefront of light-matter interactions. In atomic, molecular and opticalThe free-electron lasers (FELs), a rapid developing technology as a new generation of advanced radiation sources in the last decade, provide ultra-fast, ultra-intense, ultra-short wavelength laser pulses, becoming a robust metrology to explore the forefront of light-matter interactions. In atomic, molecular and optical (AMO) physics, shortwavelength FELs manifest their benefits in exploring multi-photon nonlinear phenomena, observing and controlling reaction dynamics of electrons, atoms and molecules. Experimental advancements from simple helium atom to complex bio-molecules, from outer-shell to inner-shell electrons, from single-photon to multi-photon processes, from single pulse experiments to time-resolved pump-probe approaches, from extreme ultraviolet to hard X-ray regimes, from energy spectra to time-resolved momentum spectra, have successively achieved, all of which are accessible to observe and manipulate quantum world in aspatial scale of atoms and a temporal resolution of femtosecond. The review selects very recent illustrative experimental results in this field and presents the groundbreaking achievements in intriguing quantum behaviors of electrons, atoms and molecules under intense shortwavelength FEL field, demonstrating the fundamental aspects of AMO physics..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 10002 (2016)
Scattering
Development of Light Scattering System for Transport Properties Measurement
Zhao Guanjia, Bi Shengshan, and Wu Jiangtao
Based on the light scattering theory, a new apparatus for transport properties measurement is built. The apparatus consists of two systems which are surface light scattering system and dynamic light scattering system, for measuring the surface and bulk properties of liquid, respectively. By a proper optical design, theBased on the light scattering theory, a new apparatus for transport properties measurement is built. The apparatus consists of two systems which are surface light scattering system and dynamic light scattering system, for measuring the surface and bulk properties of liquid, respectively. By a proper optical design, the two system can share the key devices, including the laser, single photon detector and digital correlator, and also the high pressure vessel. The whole system is designed and allowed to work at the pressure of 0~10 MPa and the temperatures between 283 K and 400 K with a stability better than ±1 mK/h. Since the frequencies of capillary waves are much smaller than that of laser light, optical mixing technique and heterodyne scheme are used to extract physical information. For checking the accuracy and reliability of the system, liquid surface tension, viscosity of heptane, thermal diffusion coefficient and specific heat capacity of R134a are measured. The deviations between experimental values and reference data are 2.29%, 0.57%, 0.12%, 0.06%, respectively. The total uncertainty for the measurement of surface tension, viscosity, thermal diffusion coefficient and specific heat capacity are estimated to be 1%, 2%, 2%, 4.6% (k=2), respectively..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 12901 (2016)
Spectroscopy
Experimental Research on Cigarette Humidity and Density Detection Based on Terahertz Time-Domain Spectroscopy
Zhou Yongjun, Zhang Hui, Zhang Xuanni, and Wang Ximing
Humidity and density are important physical indicators to evaluate the quality of cigarettes. Proper humidity and density can improve the quality of the cigarettes and reduce the defective rate. To detect cigarette humidity and density, the terahertz time-domain spectra (TDS) of 3 cigarette sample groups (each group coHumidity and density are important physical indicators to evaluate the quality of cigarettes. Proper humidity and density can improve the quality of the cigarettes and reduce the defective rate. To detect cigarette humidity and density, the terahertz time-domain spectra (TDS) of 3 cigarette sample groups (each group contains 11 samples) with identical density and different humidity and 2 cigarette sample groups (each group contains 14 samples) with identical humidity and different density, are collected using the time-domain spectroscopy system. The humidity calculation model which is based on the peak attenuation ln E and the mathematical expression between cigarette density and the spectral peak in terahertz time- domain are established. Compared with the traditional method of drying and weighing, the results obtained by the humidity calculation model show that the absolute error is less than 2.5% when the humidity is lower than 20%. The cigarette density and the spectral peak in terahertz time-domain are relevant. The correlation coefficient can reach 0.9639. The detection of cigarette humidity and density based on the terahertz time-domain spectroscopy is not only feasible but also with high accuracy..
Laser & Optoelectronics Progress
- Publication Date: Nov. 20, 2015
- Vol. 53, Issue 1, 13001 (2016)
Design of Acquisition and Transmission System for Water COD Monitoring Based on UV-VIS Spectroscopy and Wireless Sensor Networks
Liu Juan, Feng Peng, Wei Biao, Wu Decao, Tang Bin, Tang Yuan, Xiong Shuangfei, Zhang Zheng, and Tang Ge
To solve the increasingly serious problem of water environment, it is of great significance to monitor chemical oxygen demand (COD) of water as the early warning of water pollution. Based on the principle of ultravioletvisible spectroscopy to measure the water quality parameter COD, the collection and transmission systTo solve the increasingly serious problem of water environment, it is of great significance to monitor chemical oxygen demand (COD) of water as the early warning of water pollution. Based on the principle of ultravioletvisible spectroscopy to measure the water quality parameter COD, the collection and transmission system of water COD monitoring information in a large area is studied by combining the wireless sensor network (WSN) technology with spectral COD monitoring technology. Based on the Coxtex-A7 hardware platform, the data compression and WSN is utilized to realize wireless real-time monitoring of water COD. The experimental results show that the system can achieve collection and effective and reliable transmission of water COD monitoring data. This system does not only have the characteristics of low power consumption, wide coverage area, fast response, and easy maintenance, but also provides a basis for the comprehensive analysis of water environment in a water basin..
Laser & Optoelectronics Progress
- Publication Date: Dec. 28, 2015
- Vol. 53, Issue 1, 13002 (2016)
Design of Multispectral Imaging Spectrometer Using Linear Variable Filter
Wang Ying, and Gong Yan
Based on the linear variable filter (LVF), a compact multispectral imaging spectrometer is designed. With a wide LVF working spectral range of 600~1100 nm, a wide spectral range scanning multispectral imaging spectrometer objective is designed, and the total length of the objective is shorter than 85 mm; its distortionBased on the linear variable filter (LVF), a compact multispectral imaging spectrometer is designed. With a wide LVF working spectral range of 600~1100 nm, a wide spectral range scanning multispectral imaging spectrometer objective is designed, and the total length of the objective is shorter than 85 mm; its distortion is less than 0.01%; the modulation transfer function is better than 0.7 for the various wavebands in full field of view at the Nyquist frequency; the spatial angular resolution reaches 1.02'. The device can get a quasi-monochromatic image and the reflectance spectra of the target by scanning and image reconstruction. The experimental results show that the spectral resolution matches the spectral bandwidth of the LVF, indicating the resolution of 9 nm at 600 nm. By the tomato maturity identification experiments, the imaging performance of the spectrometer is verified..
Laser & Optoelectronics Progress
- Publication Date: Nov. 13, 2015
- Vol. 53, Issue 1, 13003 (2016)
Vision, Color, and Visual Optics
Design and Demonstration of Multiple-Visual-Angle Suspended Display System for Dynamic Images
Huang Jiamin, Chen Enguo, and Guo Tailiang
In order to capture object image information in different visual angles and realize the synchronous output display system, a kind of suspended display system for dynamic images is designed and demonstrated, which is synchronously observed from multiple visual angles. In this system, image- projecting source combines thIn order to capture object image information in different visual angles and realize the synchronous output display system, a kind of suspended display system for dynamic images is designed and demonstrated, which is synchronously observed from multiple visual angles. In this system, image- projecting source combines the morphology information of objects from different angles of view. The source is projected into multiple-visual-angle imaging device to generate an integrated virtual image. The key parameters of four-visual-angle suspended display system are derived. The error margin of dynamic image display is defined to avoid dislocation and double-image from different angles of view. The functional relation between the error margin and source location/layer thickness is also derived and analyzed. A miniaturized prototype with the dimensions of 60 mm × 60 mm × 30 mm is fabricated for theoretical verification. Experimental results show that the proposed system can offer synchronized display from different angles of view, expand display information content and restrain geometric and chromatic aberration. The proposed system can not only realize large-area multi-visual-angle suspended display, but also achieve miniaturized and portable multi-view display. It has a broad prospect in commercial applications..
Laser & Optoelectronics Progress
- Publication Date: Dec. 23, 2015
- Vol. 53, Issue 1, 13301 (2016)
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