Journals >Laser & Optoelectronics Progress
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2017
Volume: 54 Issue 5
42 Article(s)
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Atmospheric Optics and Oceanic Optics
Effect of External Stray Light on Low-Light Imager Loaded in Fengyun-3 Day/Night Orbit Meteorological Satellite
Chen Hailong, Chen Lin, Hu Xiuqing, and Huang Yifan
Based on the introduction of the characteristics of Fengyun-3 E star (FY3E) day/night orbit meteorological satellite and low-light imager and according to FY3E orbit parameters, the Satellite Tool Kit (STK) simulation technology is used to simulate and analyze the external stray light, which comes from the sun and the Based on the introduction of the characteristics of Fengyun-3 E star (FY3E) day/night orbit meteorological satellite and low-light imager and according to FY3E orbit parameters, the Satellite Tool Kit (STK) simulation technology is used to simulate and analyze the external stray light, which comes from the sun and the moon and enters into the remote sensor (low-light imager) loaded in FY3E. The method of light shield is proposed to suppress the stray light. The results indicate that the stray light has the greatest impact on the remote sensor on 2016-12-18 when the angle between the sun vector and the normal vector of remote sensor bottom window is minimal. The effect of stray light caused by the moon on remote sensor is further analyzed, and it can be avoided when the sun shade condition is satisfied. Therefore, when we design the shade, the angle between the sun vector and the normal vector of remote sensor bottom window is only needed to consider. At present, the field-of-view of the remote sensor is 55°, and the efficiency of shading stray light is low. To improve the shading efficiency of stray light and not affact application, the field-of-view of the remote sensor should be reduced to 50° and the size of the light shield should be decreased..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50101 (2017)
Source Apportionment of Carbonaceous Aerosol Based on Aethalometer Model
Yan Mingming, Wu Jian, Shen Jiandong, Zhou Jianwu, and Chen Linghong
The source apportionment of carbonaceous aerosol in Hangzhou is carried out with aethalometer model, and the study is based on different light absorption properties of aerosols from different origins. Combined with aerosol time-of-flight mass spectrometer and data measured by aethalometer, the parameters of aethalometeThe source apportionment of carbonaceous aerosol in Hangzhou is carried out with aethalometer model, and the study is based on different light absorption properties of aerosols from different origins. Combined with aerosol time-of-flight mass spectrometer and data measured by aethalometer, the parameters of aethalometer model are corrected. The aethalometer data from Zhaohui environmental monitoring site of Hangzhou in 2015 is analyzed, and the contribution rates of biomass and fossil fuel burning to carbonaceous aerosol in Zhaohui are analyzed. The results show that the annual concentration of carbonaceous aerosol originating from fossil fuel in 2015 is 15.4 μg/m3, and the annual concentration rate is 71.8%. The monthly contribution rate of biomass burning to carbonaceous aerosol is 20%-38%. The minimum concentration rate appears in July while the maximum concentration rate appears in December, and the monthly data shows a gradient transformation. Traffic rush hours exhibit no effect on the mean diurnal pattern of absorption exponent, which means the carbonaceous aerosol may be introduced by long-range transport. The above results build the foundation for identification of Hangzhou energy consumption structure and alleviating air pollution..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50102 (2017)
Beam Wander of Partially Coherent Anomalous Elliptical Hollow Gaussian Beam Propagating Through Non-Kolmogorov Turbulence
Tian Huanhuan, Xu Yonggen, Yang Ting, and Zhang Biling
Based on the non-Kolmogorov turbulence spectrum and the theory of second moments, a general analytical expression of beam wander model in non-Kolmogorov turbulence is derived. The results indicate that the beam wander depends on turbulence parameters including the generalized exponent parameter α, refractive index struBased on the non-Kolmogorov turbulence spectrum and the theory of second moments, a general analytical expression of beam wander model in non-Kolmogorov turbulence is derived. The results indicate that the beam wander depends on turbulence parameters including the generalized exponent parameter α, refractive index structure parameter C2n, turbulence outer scale L0, turbulence inner scale l0 and initial second moments of laser beam at the input plane. Taking the partially coherent anomalous elliptical hollow Gaussion beam (PCAEHGB) as an example, we simulate the root-mean-square (RMS) beam wander Bw and the relative beam wander Br numerically. It shows that Bw and Br increase with the increasing generalized exponent parameter, refractive index structure parameter, turbulence inner scale, turbulence outer scale, coherence length and beam waist radius. The results also indicate that Bw≈0.22 m when C2n=10-14 m3-α and the total propagation path length L=10 km, and Br reaches the maximum value when L≈5 km. Furthermore, PCAEHGB is less affected by turbulence than Gaussian-Schell model beam under the condition of the same parameters..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50103 (2017)
Fiber Optics and Optical Communications
Growth Law of High Temperature Resistance Regenerated Fiber Grating
Nie Ming, Zhang Dongsheng, Wu Mengqi, and Zhang Chunfeng
The erasing time and the regeneration complete time of fiber grating exponentially decay with temperature in the temperature interval of 800-950 ℃ when the erasing temperature and the regeneration temperature are the same. According to the fitting function of regeneration complete time, the regeneration threshold tempeThe erasing time and the regeneration complete time of fiber grating exponentially decay with temperature in the temperature interval of 800-950 ℃ when the erasing temperature and the regeneration temperature are the same. According to the fitting function of regeneration complete time, the regeneration threshold temperature of ultraviolet hydrogen loading standard communication fiber grating is 805 ℃. The reflectivity of regenerated fiber grating obeys Gaussian distribution when the treatment temperature is set between 855-905 ℃, which describes the whole regeneration process of fiber grating quantitatively. When the erasing temperature and the regeneration temperature are different, a new method to create a regenerated fiber grating with high reflectivity is obtained, and the method can improve the reflectivity of regenerated fiber grating used in ultraviolet hydrogen loading standard communication fiber from 20% to 43%..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50601 (2017)
Long-Distance Visible Light Communication Based on Light Emitting Diode Source
Zhang Yufei, Zhang Hongming, Wang Peng, Liu Tao, Sun Dedong, and Song Jian
A long-distance outdoor communication experiment based on a commercial light-emitting diode (LED) source is carried out. In the experiment, the LED source is modulated by on-off keying (OOK) modulation. The low-density parity-check (LDPC) error-correcting code is used at the receiver. The outdoor light communication exA long-distance outdoor communication experiment based on a commercial light-emitting diode (LED) source is carried out. In the experiment, the LED source is modulated by on-off keying (OOK) modulation. The low-density parity-check (LDPC) error-correcting code is used at the receiver. The outdoor light communication experiment with communication distance of 1 km is accomplished at clear daytime when the beam of LED is launched with divergence angle of 3° and modulation rate of 23 MHz (net data transmission rate is 11.5 Mbit/s), and the bit error rate of 10-6 is achieved. The experimental result shows that the data transmission rate with LDPC (4000, 2000) code is 2.4 times than that without coding when the bit error rate is 10-4. The experimental system is not need to accurate collimation and can overcome the negative environmental consequences such as the wind shaking and the atmospheric turbulence..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50602 (2017)
Image Processing
Gradient-Based Wang Tiles Texture Synthesis Algorithm with Adaptive Block Size
Tan Yongqian, and Zeng Fanju
Based on the Wang Tiles texture synthesis algorithm, the effects of texture gradient structure information, texture blocks with adaptive size, and Tile set generation method on the texture synthesis quality and time are studied. The color error and gradient information of the texture blocks are both used as the standarBased on the Wang Tiles texture synthesis algorithm, the effects of texture gradient structure information, texture blocks with adaptive size, and Tile set generation method on the texture synthesis quality and time are studied. The color error and gradient information of the texture blocks are both used as the standard to measure the similarity of two blocks in the texture synthesis algorithm. It is better than the traditional texture synthesis algorithm, which only considers the color error to determine the similarity of two texture blocks. Meanwhile, using the optimized block size for texture synthesis, the texture synthesis time is reduced. In addition, using the improved Tile set to achieve texture synthesis, we can achieve better results than those of the traditional methods. Experimental results show that this algorithm can improve both the quality and the speed of texture synthesis, compared with the traditional Wang Tile-based algorithm..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51001 (2017)
Palm Vein Recognition Based on Gabor Wavelet and NBP Algorithm
Lin Sen, Xu Tianyang, and Wang Ying
In order to extract the texture features of palm vein image and improve the recognition rate effectively, a texture feature extraction method based on joint Gabor wavelet and neighbor binary pattern (NBP) is proposed. Considering the difference of vein thickness and extension direction in venous structure, this method In order to extract the texture features of palm vein image and improve the recognition rate effectively, a texture feature extraction method based on joint Gabor wavelet and neighbor binary pattern (NBP) is proposed. Considering the difference of vein thickness and extension direction in venous structure, this method obtains multiple Gabor-magnitude features by convoluting the region of interest of the palm vein image with Gabor wavelet of four scales and four directions. And the Gabor scale-mean pattern (GSP) is obtained by averaging four different scales. The GSP neighbor binary pattern (GSPNBP) is extracted from each GSP block using the NBP description operator. Then the concatenation of the coding sequences of these multi-scale and multi-direction GSPNBP regions is used as the feature vector of the palm vein. Finally, the similarity of the two vein images is calculated by Hamming distance of the feature vectors, and the experiments are carried out in the PolyU and self-built database, respectively. Experimental results show that the highest recognition rate of this algorithm can be reached to 99.7935% and 99.3965%, respectively, and the recognition time is less than 1s, which effectively enhances the robustness of the algorithm..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51002 (2017)
Corner Detection Algorithm Based on Local Weighted Entropy and Adaptive Threshold
Wang Min, Liu Tao, and Yun Weiguo
In terms of the application of Harris algorithm, since the less real-time and a large amount of computation together with poor anti-noise ability and other issues, an improved corner detection algorithm is proposed based on the Harris, combing the local weighted entropy with minimum intensity change (MIC) algorithm. FiIn terms of the application of Harris algorithm, since the less real-time and a large amount of computation together with poor anti-noise ability and other issues, an improved corner detection algorithm is proposed based on the Harris, combing the local weighted entropy with minimum intensity change (MIC) algorithm. First of all, the candidate corner point set is computed through the local weighted entropy algorithm. Then the candidate corner is divided into three categories according to the corner response function (CRF) value of Harris algorithm. Finally, the best matching corners are obtained through the adaptive template and MIC algorithm of the threshold. Experimental results show that the proposed algorithm can improve the real-time of the original algorithm, increase the quantity of the corner extraction with better accuracy, and remove the most false corners effectively..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51003 (2017)
Performance Comparison of Absolute Difference Function and Absolute Difference Function-Squared Using in Solar Granulation Images
Zhou Hangcheng, Rao Xuejun, and Rao Changhui
In solar adaptive optics system, the correlation algorithm is commonly used with low contrast extended objects to measure wave-front error. On the basis of theoretical analysis and comparison of measurement error of absolute difference function and absolute difference function-squared using parabolic interpolation, theIn solar adaptive optics system, the correlation algorithm is commonly used with low contrast extended objects to measure wave-front error. On the basis of theoretical analysis and comparison of measurement error of absolute difference function and absolute difference function-squared using parabolic interpolation, the solar granulation images collected from real scene are used to validate the two algorithms experimentally. The result indicates that the correlation function of absolute difference function-squared better accords with parabolic distribution than the absolute difference function. The measurement accuracy of absolute difference function-squared is better than absolute difference function when using parabolic interpolation..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51004 (2017)
Anisotropic Total Variation Guided Filtering and Its Split Bregman Algorithm
Lu Bibo, Wang Lerong, Wang Yongmao, and Zheng Yanmei
An ideal guided image with good structure is the key to guided filtering (GF) denoising. In order to improve the denoising effect of the GF, an anisotropic total variation (ATV) based on the GF is proposed. First, the noisy image is smoothed by the ATV model to obtain a good structure information image. Then the image An ideal guided image with good structure is the key to guided filtering (GF) denoising. In order to improve the denoising effect of the GF, an anisotropic total variation (ATV) based on the GF is proposed. First, the noisy image is smoothed by the ATV model to obtain a good structure information image. Then the image is served as the guided image in the GF algorithm. And an iterative processing is used for improving the algorithm robustness. Considering that the traditional iterative method for the total variation model is time consuming, the Split Bregman iterative method is introduced to speed up the whole process. The experimental results indicate that the proposed method not only has certain advantages in peak signal noise ratio, normalized mean square error and structural similarity, but also increases the computation speed by nearly 30 times compared with the related traditional iterative method. It can effectively remove the noises while preserving more structure and edge details..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51005 (2017)
Active Contour Segmentation Model Based on Local and Global Gaussian Fitting
Zhao Fangzhen, Liang Haiying, Wu Xianglin, and Ding Dehong
The active contour model based on the local Gaussian fitting utilizes the average and variance information to fit the image information. Compared with the traditional active contour models which only utilize the gray average information, this model can segment the complex medical image successfully. However, this modelThe active contour model based on the local Gaussian fitting utilizes the average and variance information to fit the image information. Compared with the traditional active contour models which only utilize the gray average information, this model can segment the complex medical image successfully. However, this model only utilizes the local information of image to model, so the convergence speed is slow. In addition, the traditional Heaviside function is utilized to establish the energy function, which leads to the limited segmentation accuracy. Aimed at these defects, the global Gaussian fitting term is introduced to improve the Heaviside function. Using the method of adaptive adjustment, an active contour segmentation model based on the local and global Gaussian fitting is obtained. The improved model can not only segment the images with same average but different variance, but also segment the inferior medical images effectively, and the performance of the improved model is verified by experiments..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51006 (2017)
Imaging Systems
Design of Approximate Concentric Sphere Large Format X-Ray Streak Tube
Zhang Jingjin, and Yang Qinlao
X-ray streak camera is requested to obtain as much information as possible in single measurement because of the picoseconds duration in plasmas diagnosis. An effective method is to enlarge the imaging area. An X-ray streak tube is designed based on the electrostatic focusing system of bi-electrode concentric sphere to X-ray streak camera is requested to obtain as much information as possible in single measurement because of the picoseconds duration in plasmas diagnosis. An effective method is to enlarge the imaging area. An X-ray streak tube is designed based on the electrostatic focusing system of bi-electrode concentric sphere to solve the problem of imaging quality for large format. Through simulation of the electrons emission by Monte Carol methods and tracing the electron trajectories by Runge-Kutta, the calculation shows that the effective working area of photocathode is 50 mm, central static limit spatial resolution is 50 lp/mm, edge static limit spatial resolution is 31 lp/mm, the magnification is 1.1, the length is 600 mm, and the diameter is 100 mm. The results show that it can satisfy the requirement of large format imaging and can be applied in the process of ultrafast event to obtain lots of information..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51101 (2017)
Flat-Top Sinusoidal Phase Mask Coronagraph
Tong Xiegang, Cao Qing, Teng Da, and Wang Kai
A flat-top sinusoidal phase mask coronagraph is theoretically studied, it is the generalized form of the sinusoidal phase mask coronagraph and the six-level phase mask coronagraph. This kind of phase mask is a double-periodic phase mask with both the flat-top sinusoidal and the constant parts in the azimuthal phase in A flat-top sinusoidal phase mask coronagraph is theoretically studied, it is the generalized form of the sinusoidal phase mask coronagraph and the six-level phase mask coronagraph. This kind of phase mask is a double-periodic phase mask with both the flat-top sinusoidal and the constant parts in the azimuthal phase in each period. The wideband working condition for this kind of phase mask is analytically presented. On one end, the wideband working condition reduces to that of a sinusoidal phase mask. And on the other end, it reduces to that of a six-level phase mask. Just like its two special examples, the numerical calculation shows the flat-top sinusoidal phase mask coronagraph generally has the advantage of achromatism..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51102 (2017)
Instrumentation, Measurement and Metrology
Study of Laser Beam Autocollimation System
Ye Chengliang, Shang Jianhua, and He Yan
In order to realize rapid autocollimation of laser beam, decrease the error during manual adjustment of laser beam, and increase real-time performance and friendliness of man-machine interface operation, a visual autocollimation system for laser beam is designed. Secondary development of MV-U2000 image collecting modulIn order to realize rapid autocollimation of laser beam, decrease the error during manual adjustment of laser beam, and increase real-time performance and friendliness of man-machine interface operation, a visual autocollimation system for laser beam is designed. Secondary development of MV-U2000 image collecting module is carried out with the help of the VC++. The acquisition, real-time display and storage of the image of the laser spot are realized. Through the serial communication between the PC and the STM32, rapid adjustment of laser beam is realized by auto-adjusting the step size of stepper motor. Then, the laser beam collimation is achieved. The experiment results show that the autocollimation system satisfies the application requirement of collimation. The single operation lasts for 2 min and the measurement precision is up to 4.17 μrad. The system has the characteristics of high-integration, user-friendliness and high-transportability..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51201 (2017)
Influencing Factors of Upper Limit for Particle Velocity Measurement Using Single-Frame Long-Exposure Method
Feng Mingliang, Zhou Wu, and Cai Xiaoshu
In order to improve the upper limit of particle velocity measurement for single-frame long-exposure imaging method, influence factors of upper limit for velocity measurement are theoretically analyzed and experimentally researched with backlit imaging single-frame long exposure method from the perspective of image grayIn order to improve the upper limit of particle velocity measurement for single-frame long-exposure imaging method, influence factors of upper limit for velocity measurement are theoretically analyzed and experimentally researched with backlit imaging single-frame long exposure method from the perspective of image grayscale. The results show that for backward illumination, higher particle velocity leads to higher gray value of particle image and more difficult to distinguish it. From the perspective of track recognition, the influencing factors mainly include the particle diameter, the particle transmittance and the intensity of light source. It is found that the upper limit of velocity measurement for the opaque disk particle with the diameter of 50 μm reaches 1250 m/s by using the backlit imaging single-frame long exposure method velocity measurement device when the intensity of the light source is high enough..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51202 (2017)
Fast and Stable White Light Interferometry
Dong Yifan, Wan Xinjun, Meng Han, and Xie Shuping
To reduce the sampling data and the computational cost of white light interferometry, and improve the measurement speed, fast and stable white light interferometry is proposed. The mathematical model of light interferometry is deduced from the white light interference microscope model, and the relationship between lighTo reduce the sampling data and the computational cost of white light interferometry, and improve the measurement speed, fast and stable white light interferometry is proposed. The mathematical model of light interferometry is deduced from the white light interference microscope model, and the relationship between light interference intensity function and envelop function is confirmed. On the basis of these studies, the envelope algorithm of Hilbert transform function extracting interference signal is proposed by increasing the sampling interval of discrete sampling point. And the sampling interval that satisfies the condition of the proposed algorithm is analyzed and determined based on the sampling principle. The algorithm effectiveness is then verified by a simulation test. The white light interference intensity signal of the sample has the direct current (DC) bias noise, which affects the stability of the fast white light interference measurement method. Therefore, median filtering method is used to eliminate background noise. And the quality of the filtered light intensity envelope is analyzed. The white light interference images of the sample are collected by a white light interference microscope, and the three-dimensional surface topographies reconstructed with different sampling intervals are compared. The results show that the envelope algorithm can improve the speed of three-dimensional reconstruction by 20 times compared with the traditional method. Meanwhile, the stability is improved as well..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51203 (2017)
Extended Pseudo-Random Coding Rules with Different Repetition Frequency Based on Single Photon Detection
Chen Yu, and Yang Yi
The extended pseudo-random encoding can solve the problem of the fuzzy distance, which is brought by high repetition frequency laser ranging in long target distance. But the extended pseudo-random coding methods are diverse. The effects of different amplitude encoding modes on the ranging accuracy are studied under difThe extended pseudo-random encoding can solve the problem of the fuzzy distance, which is brought by high repetition frequency laser ranging in long target distance. But the extended pseudo-random coding methods are diverse. The effects of different amplitude encoding modes on the ranging accuracy are studied under different laser source repetition frequencies, and the Matlab simulation is carried out. The theory and simulation results show that the probability of "1" in optimal coding trends from 1 to nearly 1/2 with the increase of repetition frequency. When the probability is 1/2, the randomness is the best and the detection efficiency is high. The peak value is still obvious in weak noise environment. Therefore, in the practical application of distance measurement, choosing the appropriate coding method according to different repetition frequencies can optimize the ranging algorithm and improve the ranging efficiency..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51204 (2017)
Simultaneous Detection of Multi-Cable Faults Based on Noise Time-Domain Reflectometry
Ma Peiguo, Xu Hang, Wang Bingjie, and Wu Guanghui
In order to simultaneously detect the cable faults on different branches of the cable bundles and multi-core cables, a multi-channel noise time domain reflectometry is proposed and experimentally demonstrated. Amplified spontaneous emission (ASE) noises after multipath filtering serve as probe signals to detect differeIn order to simultaneously detect the cable faults on different branches of the cable bundles and multi-core cables, a multi-channel noise time domain reflectometry is proposed and experimentally demonstrated. Amplified spontaneous emission (ASE) noises after multipath filtering serve as probe signals to detect different branches of cable bundles or multi-core cables. Based on correlation detection technology, the cable faults of different branches are detected simultaneously with no mutual interference. The experimental results indicate that the proposed method can detect open circuits, short circuits and impedance mismatches on different cable branches simultaneously. Moreover, for the single URM43 coaxial cable, a maximum detection range of about 720 m is obtained when the power of the noise detection signal is -9.1 dBm. In addition, it is experimentally proved that the proposed method can realize live test of cable fault..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51205 (2017)
Lasers and Laser Optics
Path Planning of Laser Cladding and Remanufacturing Based on Reverse Engineering
Wang Xinlong, Sun Wenlei, Zhang Jianjie, and Huang Yong
In order to improve the cladding processing efficiency and quality of curved surface parts and achieve off-line programming, the cladding path planning of curved surface parts is carried out according to the process characteristics of laser cladding. The modeling of parts is done based on the reverse engineering. A patIn order to improve the cladding processing efficiency and quality of curved surface parts and achieve off-line programming, the cladding path planning of curved surface parts is carried out according to the process characteristics of laser cladding. The modeling of parts is done based on the reverse engineering. A path generation method based on the tangent plane method is proposed according to the model. The distance between the tangential planes is determined by analyzing the overlap rate of cladding tracks. The interpolation point set along the trajectories is obtained by using defocusing amount for effective processing, and the normal vector is determined by calculating the location of interpolation points on the triangular patch. The position and attitude of the laser nozzle are calculated with the offset method. The morphology and structural property of cladding layer on surfaces are analyzed. Compared with general path planning algorithms, the proposed method, based on the premise of satisfying laser cladding process parameters, comprehensively considers many kinds of factors such as the track row spacing and the spot size. The cladding efficiency and quality are improved, which is beneficial to the promotion of laser cladding in the remanufacturing field of curved surface parts..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51401 (2017)
Theoretical Study on Femtosecond Laser Heating of Two-Layer Metal Films
Chen Anmin, He Ximing, Fei Dehou, and Jin Mingxing
The thermal behavior of single-layer Ag film or Ag/Au and Ag/Cu two-layer films irradiated by femtosecond laser is studied with the two-temperature model. The corresponding distributions of electron temperature and lattice temperature versus time and space are calculated. The results show that the two-layer metal strucThe thermal behavior of single-layer Ag film or Ag/Au and Ag/Cu two-layer films irradiated by femtosecond laser is studied with the two-temperature model. The corresponding distributions of electron temperature and lattice temperature versus time and space are calculated. The results show that the two-layer metal structure can change the lattice temperature of the top Ag layer, and then change its damage threshold. When selecting chromium with a larger electron-lattice coupling coefficient as the bottom layer metal for Ag film, the damage threshold of the top Ag layer is further enhanced. These results provide important guiding significance for using Ag films to manufacture the reflective mirrors for visible femtosecond lasers..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51402 (2017)
Effect of Annealing on Optical Structures Fabricated by Femtosecond Laser Irradiation Inside Polymethyl Methacrylate
Pang Bo, Patricia Scully, Anca Taranu, and Alisdair Macpherson
An optical structure with refractive index change (Δn) is written out inside polymethyl methacrylate (PMMA) by a femtosecond laser with laser direct writing technique, and the volume gratings are fabricated. One group of volume gratings is kept at room temperature, and the other group is annealed. By the experimental cAn optical structure with refractive index change (Δn) is written out inside polymethyl methacrylate (PMMA) by a femtosecond laser with laser direct writing technique, and the volume gratings are fabricated. One group of volume gratings is kept at room temperature, and the other group is annealed. By the experimental comparison between the two groups, the effect mechanism of annealing on Δn is explored. The experimental results show that, there exists no obvious difference in feature size of optical structure caused by annealing, and the intensity of Raman peak at 1640 cm-1 is increased as a consequence of annealing, which corresponds to the increase of Δn. Meanwhile, optical structures with refractive index change inside PMMA induced by femtosecond lasers are not stable. The Δn value increases slowly with the increase of time, and annealing treatment can accelerate this increase..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51403 (2017)
Microstructure and Property of Al2CrFeCoCuNixTi High Entropy Alloy Coatings Prepared by Laser Cladding
Qiu Xingwu, Liu Chunge, and Zhang Yunpeng
The Al2CrFeCoCuNixTi high entropy alloy coating on Q235 steel surface is prepared by laser cladding. Its microstructure is analyzed, and its mechanical property and corrosion resistance are tested. The results show that the microstructure of cladding zone in the Al2CrFeCoCuNixTi high entropy alloy coating is mainly comThe Al2CrFeCoCuNixTi high entropy alloy coating on Q235 steel surface is prepared by laser cladding. Its microstructure is analyzed, and its mechanical property and corrosion resistance are tested. The results show that the microstructure of cladding zone in the Al2CrFeCoCuNixTi high entropy alloy coating is mainly composed of equiaxed grains with distribution of precipitates. The phase structure of this coating is mainly composed of face-centered-cubic structure, body-centered-cubic structure and Laves phase. With the increase of Ni content, the relative wear resistance of this coating increases first and then decreases with a value of 2.0-3.6. The wear resistance of this coating is affected by both plasticity and hardness. The coatings have excellent corrosion resistance in the 0.5 mol/L H2SO4 solution, and the difference of corrosion resistance mainly depends on the structural components of coatings..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51404 (2017)
Mid-Infrared Raman Laser Source Based on Liquid-Core Fiber
Tian Cuiping, Wang Yingying, Shi Hongxing, Cheng Zhaochen, and Wang Pu
An integrated structure of liquid-core fiber mid-infrared Raman laser source is established, and an all-fiber structure liquid-core coupling device is used to pump injection. A nanosecond laser with center wavelength of 1064 nm, repetition rate of 5 kHz and maximum output power of 55 mW is used as pump source, and a hoAn integrated structure of liquid-core fiber mid-infrared Raman laser source is established, and an all-fiber structure liquid-core coupling device is used to pump injection. A nanosecond laser with center wavelength of 1064 nm, repetition rate of 5 kHz and maximum output power of 55 mW is used as pump source, and a hollow core fiber is filled with the mixture with different proportions of carbon tetrachloride and carbon disulfide. At least seven-order Raman signal is achieved, and the longest wavelength of 2.08 μm and the minimum Raman threshold of 0.3 mW can be measured. The fiber coupling efficiency larger than 90% is achieved when we establish the liquid-core fiber coupling device with all-fiber structure. We also find that the Raman signal generated by silica fiber plays a prominent role in the generation of stimulated Raman scattering..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51405 (2017)
Efficient Coupling Method of Laser Based on Graded-Index Fiber
Liu Peng, and Wang Chenglin
The mechanism based on graded-index fiber (GIF) is provided for efficient coupling between laser diode (LD) and single mode fiber (SMF). As the central component, the GIF is placed in front of SMF. A large-sized elliptical core is designed in GIF for matching the far field of LD, and the beam from LD can be focused andThe mechanism based on graded-index fiber (GIF) is provided for efficient coupling between laser diode (LD) and single mode fiber (SMF). As the central component, the GIF is placed in front of SMF. A large-sized elliptical core is designed in GIF for matching the far field of LD, and the beam from LD can be focused and coupled into SMF. By analyzing with finite difference beam propagation method, the power coupling efficiency is able to reach 88%. For 1 dB insert loss, the tolerance in fiber length of GIF is 75 μm, and the tolerances of offset in the direction of major axis and minor axis are 28 μm and 10 μm, respectively. The scheme is useful for the design of high power LD coupling single mode tail fiber..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51407 (2017)
Machine Vision
Static Saliency Region Detection in Traffic Scenes
Fang Zhiming, Cui Rongyi, and Jin Jingxuan
The traffic scene saliency detection can provide important information for the automatic decision or driving assist system. Based on the underlying visual characteristics, a new method for the rapid saliency detection in traffic scene is proposed, which is based on the singular value decomposition of multi-feature spacThe traffic scene saliency detection can provide important information for the automatic decision or driving assist system. Based on the underlying visual characteristics, a new method for the rapid saliency detection in traffic scene is proposed, which is based on the singular value decomposition of multi-feature space (the color space and the opposition color space). First of all, in the brightness space, using the singular value decomposition to estimate the high light region and suppress the high light area to detect the brightness saliency. Secondly, in the dual opposition color space, the region of partial singular value reconstruction is retained as the color feature saliency region. Finally, the saliency region of each feature space is added together and the saliency region is the candidate region of the target detection of traffic scene. Experimental results show that the proposed method has good robustness in illumination variation and complex background scenes..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51501 (2017)
Nonlinear Optics
Frequency Doubling Effect of Topological Charge of Composite Vortex in Frequency Doubling Process
Zhao Yuanli, Li Fangshu, Qiu Xiaodong, Zhang Wuhong, Lu Qinghong, and Chen Lixiang
Higher-order vortex light field generated through the process of nonlinear frequency conversion gets the researcher′s attention, but the most researches on this field concentrate on Laguerre-Gaussian beams rather than the nonlinear frequency conversion process of composite vortex. The process of frequency doubling of cHigher-order vortex light field generated through the process of nonlinear frequency conversion gets the researcher′s attention, but the most researches on this field concentrate on Laguerre-Gaussian beams rather than the nonlinear frequency conversion process of composite vortex. The process of frequency doubling of composite vortex is analyzed theoretically, and the vortex distribution of frequency doubling light field is obtained. Via theoretically studying, the topological charge conservation in the frequency doubling process of composite vortex is demonstrated. The topological charge conservation of Laguerre-Gaussian vortex light in the frequency doubling process based on nonlinear potassium titanyl phosphate optical crystal is experimentally demonstrated. Furthermore, composite vortex light is generated based on Mach-Zenhder interferometer, and its frequency doubling process is studied. Experimental results confirm the topological charge conservation in the frequency doubling process of composite vortex light..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 51901 (2017)
Optical Design and Fabrication
Design Method of Diffuse Reflection Freeform Surface
Zhu Zhenmin, and Luo Hui
A method is proposed to design a freeform surface profile, which can make the illumination uniformity of the target surface location be a constant and can be used in the diffuse reflection surface indirect illumination system. Based on the ideal diffuse reflection freeform surface and light emitting diode Lambertian chA method is proposed to design a freeform surface profile, which can make the illumination uniformity of the target surface location be a constant and can be used in the diffuse reflection surface indirect illumination system. Based on the ideal diffuse reflection freeform surface and light emitting diode Lambertian characteristics, equations of target plane illuminance distribution function are derived. The surface profile data is obtained by solving the equations. The diffuse reflection freeform surface is obtained by rotating around the axis. According to the illumination of the target surface, the evaluation function is built to optimize the solution of the array spacing. The non-sequential ray tracing simulation of the system is carried out by using TracePro software. The simulation results show that the target surface size is 50 mm circular area, the illumination distance is 200 mm under the indirect illumination of diffuse reflection freeform surface, the uniformity is 91.5%, and the effectiveness is 6.73%. Indirect illumination and direct illumination at diffuse reflection freeform surface for space optimized linear array, circular array and rectangular array are compared. Illumination uniformity of diffuse reflection freeform surface indirect illumination is better than that of direct illumination. The simulation results verify the correctness and effectiveness of the scheme..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 52201 (2017)
Optical Devices
AlGaInP Light Emitting Diode with Coupled Distributed Bragg Reflector Structure
Zheng Yuanyu, Wu Chaoyu, Lin Feng, Wu Mingyue, Zhou Qilun, and Li Shuiqing
An AlAs/Al0.5Ga0.5As coupled distributed Bragg reflector (DBR) with three different reflection center wavelengths is fabricated by the metal-organic chemical vapor deposition system. The transmission electron microscopy and X-ray diffractometer are used to characterize the structure, thickness, and composition. The whiAn AlAs/Al0.5Ga0.5As coupled distributed Bragg reflector (DBR) with three different reflection center wavelengths is fabricated by the metal-organic chemical vapor deposition system. The transmission electron microscopy and X-ray diffractometer are used to characterize the structure, thickness, and composition. The white light reflectance spectroscopy is used to characterize the intensity and bandwidth of the reflection spectrum. The result shows that coupled DBR has higher reflectance spectrum intensity and wider bandwidth compared to conventional DBR and coupled DBR with two reflection center wavelengths. AlGaInP light emitting diode (LED) with coupled DBR is prepared, and the size is 6.0 mil×6.0 mil (1 mil=0.0254 mm). Under the measuring current of 20 mA, the output optical power is 3.54 mW, the luminous efficiency is 17.26 lm/W, and the external quantum efficiency is 8.77%. The output power of LED is 35.1% higher than that of conventional DBR, and 11.3% higher than that of the coupled DBR with two reflection center wavelengths. It shows that the coupled DBR with three reflection center wavelengths can remarkably increase the light extraction efficiency of an AlGaInP LED..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 52301 (2017)
Study on Aging Properties of AlGaInP Light Emitting Diode
Zheng Yuanyu
A chip with an area of less than 12 mil×12 mil (300 μm×300 μm, 1 mil=25.4 μm) is fabricated using a metal organic chemical vapor deposition system epitaxial AlGaInP light emitting diode. The chip is packaged in a bare crystal structure and accelerated at 50 mA, 50 ℃ condition for 1008 h aging experiment. The A chip with an area of less than 12 mil×12 mil (300 μm×300 μm, 1 mil=25.4 μm) is fabricated using a metal organic chemical vapor deposition system epitaxial AlGaInP light emitting diode. The chip is packaged in a bare crystal structure and accelerated at 50 mA, 50 ℃ condition for 1008 h aging experiment. The purpose of the experiment is to investigate the effects of distributed Bragg reflectors (DBR) and segmented doped P-type layers on the aging properties of small-sized chips with different doping concentrations in epitaxial structures. Results show that as the chip size shrinks, the light attenuation becomes larger. Increasing DBR doping concentration can significantly reduce the light attenuation when the chip size is less than 9 mil×9 mil (225 μm×225 μm). In addition, segmented doped P-cladding are prepared by reducing the doping concentration between the P-Al0.5In0.5P layer and transition layer, and reducing the second P-Al0.5In0.5P doping concentration can further enhance the aging properties. The light attenuation can be controlled within -6% for the aging experiment under the 50 mA constant current at 50 ℃ to 1008 h with chip size of 6 mil×6 mil (150 μm×150 μm)..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 52302 (2017)
Reshaping Characteristics of Multilevel All-Optical Amplitude Regenerators
Jiang Shanglong, Wu Baojian, Sun Fan, Kong Xiangjian, and Qiu Kun
Linear gain and gain slope are proposed to describe the amplification and reshaping characteristics of multilevel all-optical amplitude regenerators. The reshaping range, the optimal operating point, and the number of regenerative levels can be determined based on the gain slope curve of the multilevel all-optical amplLinear gain and gain slope are proposed to describe the amplification and reshaping characteristics of multilevel all-optical amplitude regenerators. The reshaping range, the optimal operating point, and the number of regenerative levels can be determined based on the gain slope curve of the multilevel all-optical amplitude regenerators. We focus on Mach-Zehnder interferometer (MZI)-based multilevel all-optical amplitude regenerator with a gain slope curve of cosine oscillation. The smaller the signal oscillating amplitude is, the more the regenerative level numbers are. The results show that the amplitude noise of pulse-amplitude-modulating signal which is through MZI multilevel all-optical amplitude regenerator can be suppressed greatly, while the phase jitter is increasing..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 52303 (2017)
Optics at Surfaces
Energy-Band Structure and Density of States of Composite Lattice Two-Dimensional Graphene Plasmon Polariton Crystals
Qiu Pingping, Qiu Weibin, Lin Zhili, Chen Houbo, Ren Junbo, Wang Jiaxian, Kan Qiang, and Pan Jiaoqing
A composite lattice two-dimensional graphene plasmon polariton crystal structure is proposed, which composed of periodically arranged primitive cells with four graphene nanodisks. The energy-band structure and density of states of graphene plasmon polariton crystals are obtained by iteratively solving the eigenfrequencA composite lattice two-dimensional graphene plasmon polariton crystal structure is proposed, which composed of periodically arranged primitive cells with four graphene nanodisks. The energy-band structure and density of states of graphene plasmon polariton crystals are obtained by iteratively solving the eigenfrequencies with the finite element method. The numerical simulation results show that, in the proposed structure, there exists a complete photonic bandgap with a bandgap width of 5.7 THz, and the position and width of this bandgap can be tuned by modifying the chemical potential of graphene. The proposed structure can be applied in the techniques such as high density surface plasmon polariton integrated circuit and on-chip plasmon polariton interconnection..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 52401 (2017)
Reviews
Large-Scale Photonic Integration Technologies Based on Multi-Project Wafer Flow Sheet
Zheng Xiu, and Liu Yong
With the rapid growth of communication capacity of optical networks, integrating discrete optical devices into a single chip to reduce footprint and cost becomes a development of optoelectronic devices. Photonic integrated circuit has many advantages such as small footprint, low power consumption and light weight, and With the rapid growth of communication capacity of optical networks, integrating discrete optical devices into a single chip to reduce footprint and cost becomes a development of optoelectronic devices. Photonic integrated circuit has many advantages such as small footprint, low power consumption and light weight, and it is a key technology for future broad-bandwidth optical networks to solve the problems of large energy consumption, large volume and small capacity. We review three kinds of large-scale photonic integration technologies which are based on multi-project wafer flow sheets, including silicon-based photonic integration technology, Ⅲ-Ⅴ indium phosphide integration technology and TriPleX integration technology which consists of multilayer waveguides of silicon nitride and silicon oxide. Three foundries supporting multi-project wafer sheet photonic integration technologies are introduced, and some chip examples realized by these foundries are presented. The comparison of technology parameters among different foundries is carried out..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50001 (2017)
Manipulating Surface Plasmon Propagation: From Beam Modulation to Near-Field Holography
Li Tao, Chen Ji, and Zhu Shining
Surface plasmon polariton (SPP) is a kind of electromagnetic mode confined at the interface of metal and dielectric, and it is expected to be a good carrier for photonic arrangement and integration in micro/nano scale owing to its strong field enhancement and confinement properties. Along with the deep understanding ofSurface plasmon polariton (SPP) is a kind of electromagnetic mode confined at the interface of metal and dielectric, and it is expected to be a good carrier for photonic arrangement and integration in micro/nano scale owing to its strong field enhancement and confinement properties. Along with the deep understanding of SPP properties and the increasing requirement for developing micro/nano optical devices, how to precisely control the propagation of SPP waves and realize the specific distribution of near-field intensity has become the focus. We review the new principles and methods of manipulating the SPP beams by micro/nano structures, and the enhanced ability to control the beam property and the near-field distribution. The basic characteristics, the generation and the control of the special plasmon beams, including Airy beams, diffraction-free collimating beams and angular Bessel beams, are mainly addressed, which has been extended to near-field holography recently. The possible applications of novel micro/nano photonics devices based on SPP manipulation are discussed as well..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50002 (2017)
Mode Conversion and Coupling in Silicon-Based Nanometer Photonic Integrated Circuits
Li Chenlei, and Dai Daoxin
With ultra-high index contrast and ultra-small cross sections, silicon nanometer optical waveguides have super light field limit ability and provide a very promising way to realize nano-photonic integrated circuits with high integration density. It is well-known that mode conversion and coupling play an important role With ultra-high index contrast and ultra-small cross sections, silicon nanometer optical waveguides have super light field limit ability and provide a very promising way to realize nano-photonic integrated circuits with high integration density. It is well-known that mode conversion and coupling play an important role for realizing various functionality elements in photonic integrated circuits. The theory of mode conversion and coupling new structures and devices in silicon photonics integrated circuits are analyzed and discussed in detail. The mode transmission and evolution process of silicon nanometer optical waveguide tapered structure are studied, and the unique polarization-dependent mode conversion mechanism is revealed. The results show that when asymmetry exists in the cross section of the optical waveguide, it is possible to produce polarization mode miscellaneous in some specific waveguide widths. Which provide a convenient method for realizing polarization rotation. By adjusting the phase matching conditions of mode conversion and coupling in asymmetric directional coupled structures, important approaches for realizing ultra-small polarization-beam splitters as well as broadband mode multiplexers/demultiplexers are provided..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50003 (2017)
Research Progress in Planar Waveguide Lasers
Chen Silu, Liu Qi, Meng Junqing, and Chen Weibiao
The planar waveguide lasers are the good combination of slab lasers and fibre lasers, which combine the advantages of both while avoiding their each disadvantages. The high aspect-ratio allowing for efficient one-dimensional heat flow from the active region, leads to controlling the thermal lens effect well and controlThe planar waveguide lasers are the good combination of slab lasers and fibre lasers, which combine the advantages of both while avoiding their each disadvantages. The high aspect-ratio allowing for efficient one-dimensional heat flow from the active region, leads to controlling the thermal lens effect well and controlling the beam quality excellently. By increasing the width and length of the active-region, the high output power is obtained, and the waveguide structure which has a numerical aperture does a great job in constraining the non-diffraction limited pumping light, leading to the high brightness of the lasers. Introductions about the fabrication, materials and history of planar waveguide lasers are made. The reported studies relating to the planar waveguide lasers are reviewed, and the prospect of the further progress is given..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50004 (2017)
Study Progress of Organic Polymeric Optical Waveguides
Hou Youjun
Compared with inorganic semiconductor optical waveguides, organic polymer waveguides have obvious advantages such as easy processing and convenient integration. Research status of organic polymer optical waveguides is summarized, where the material classification and the fabrication of polymer optical waveguides are inCompared with inorganic semiconductor optical waveguides, organic polymer waveguides have obvious advantages such as easy processing and convenient integration. Research status of organic polymer optical waveguides is summarized, where the material classification and the fabrication of polymer optical waveguides are included. The application status of polymer planar optical waveguides and polymer microstructured fiber waveguides is mainly summarized. The prospect of polymer optical waveguides is discussed, and some suggestions are put forward..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50005 (2017)
Research Progress on Three-Dimensional Optical Display Technology
Sang Xinzhu, Yu Xunbo, Chen Duo, Gao Xin, Wang Peng, Xing Shujun, and Yu Chongxiu
To realize the natural three-dimensional optical display, the presentation style of real objects should be followed, and both the binocular parallax and the smooth motion parallax are required. The research status of the three-dimensional optical display both at home and abroad is reviewed. Research progresses on the dTo realize the natural three-dimensional optical display, the presentation style of real objects should be followed, and both the binocular parallax and the smooth motion parallax are required. The research status of the three-dimensional optical display both at home and abroad is reviewed. Research progresses on the dense-viewpoint display, integral imaging display, light field display and holographic display in Beijing University of Posts and Telecommunications are mainly presented. The full-parallax light field display and the holographic display represent the future development direction of three-dimensional optical display..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50006 (2017)
Progress in Directly Pumping of Mid-Infrared Solid-State Lasers
Sun Xiao, Han Long, and Wang Keqiang
Mid-infrared (3-5 μm) is in the range of atmospheric transmission window, which has broad application prospects. So far, the main way to obtain the mid-infrared radiation by solid-state lasers is based on the optical parameter oscillator (OPO) technology. The design principle and structures of new type mid-infrared lasMid-infrared (3-5 μm) is in the range of atmospheric transmission window, which has broad application prospects. So far, the main way to obtain the mid-infrared radiation by solid-state lasers is based on the optical parameter oscillator (OPO) technology. The design principle and structures of new type mid-infrared lasers, especially directly pumping of mid-infrared lasers are not so complicated compared with OPO. With the development of crystal material and relevant pump sources, the directly pumping of mid-infrared lasers develops rapidly. Directly pumping of mid-infrared lasers, their key techniques and recent research advances, represented by Fe∶ZnSe laser, Ho∶BYF laser and Dy∶PGS laser, are summarized. The key and difficult points are analyzed at last..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 50007 (2017)
Spectroscopy
Classification Method of Biological Tissues Based on Raman Spectrum Features
Zheng Jiawen, and Yang Tangwen
Biological tissues are identified based on unique features of their Raman spectra. Raman signal data of biological tissues is acquired by a self-designed Raman probe, and preprocessed to rectify the baseline through filtering noises and stray light. The principal component analysis method is used to extract the criticaBiological tissues are identified based on unique features of their Raman spectra. Raman signal data of biological tissues is acquired by a self-designed Raman probe, and preprocessed to rectify the baseline through filtering noises and stray light. The principal component analysis method is used to extract the critical Raman signal features of biological tissues, and then a back propagation (BP) neural network algorithm is used to classify the biological tissues by using these features. Automatic classification is implemented with the Raman spectrum data from the animal tissue phantoms. Experimental results show that the BP neural network is efficient to identify different animal tissues, and the accuracy rate reaches nearly 95%..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 53001 (2017)
Quantitative Analysis of Copper in Pig Feed by Single Pulse Laser Induced Breakdown Spectroscopy
Liu Shanshan, Lin Sihan, Zhang Jun, Li Jing, Liu Muhua, and Zhang Wengong
The Cu content in pig feed is quantitatively analyzed based on the single pulse laser-induced breakdown spectroscopy (LIBS), where the intensities of two characteristic spectral lines of Cu at the wavelength of 324.74 nm and Ca at the wavelength of 317.95 nm are used as the independent variables for the multi-variable The Cu content in pig feed is quantitatively analyzed based on the single pulse laser-induced breakdown spectroscopy (LIBS), where the intensities of two characteristic spectral lines of Cu at the wavelength of 324.74 nm and Ca at the wavelength of 317.95 nm are used as the independent variables for the multi-variable nonlinear regression, and the Cu content in feed is used as the dependent variable. The analysis results from the single variable method, the cross dimension-reduction nonlinear multi-variable approximation model, the nonlinear multi-variable quadric model and the square dimension-reduction nonlinear multi-variable approximation model are compared, and the samples for validation are predicted and analyzed. The results show that the cross dimension-reduction nonlinear multi-variable approximation model has the best prediction performance than the other methods in which the fitting correlation coefficient between the predicted concentration and the actual concentration is 0.9799 for the modeling set and 0.8597 for the prediction set, and the average relative error is 8.12%..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 53002 (2017)
Quantitative Measurement of Iron Content in Geological Standard Samples by Laser-Induced Breakdown Spectroscopy Combined with Artificial Neural Network
Hu Yang, Li Zihan, and Lü Tao
By using the laser-induced breakdown spectroscopy (LIBS) technique, the plasma emission spectra of the series of geological standard samples from United States Geological Survey (USGS) are obtained. By using the artificial neural network, the content of Fe in different USGS geological standard samples is measured. The By using the laser-induced breakdown spectroscopy (LIBS) technique, the plasma emission spectra of the series of geological standard samples from United States Geological Survey (USGS) are obtained. By using the artificial neural network, the content of Fe in different USGS geological standard samples is measured. The relative error between the measured content and standard content of BCR-1G, BHVO-2G, BIR-1G, GSD-1G, and GSE-1G is 1.86%, 5.73%, 0.27%, 3.86% and 2.63%, respectively, which shows that LIBS combined with artificial neural network can measure the Fe content well in the series of geological standard samples from USGS..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 53003 (2017)
Oxygen-Induced Electron Transfer Dynamic Characteristics of Single Molecules
Wu Ruixiang, Chen Ruiyun, Qiao Zhixing, Gao Yan, Zhang Guofeng, Qin Chengbing, Xiao Liantuan, and Jia Suotang
By measuring the probability density statistical characteristics of the duration time of single molecules fluorescence at on-and off-states, the effect of oxygen concentration on electron transfer dynamic characteristic of single molecules is studied. In the oxygen-rich environment, the fluorescence blinking of single By measuring the probability density statistical characteristics of the duration time of single molecules fluorescence at on-and off-states, the effect of oxygen concentration on electron transfer dynamic characteristic of single molecules is studied. In the oxygen-rich environment, the fluorescence blinking of single molecules is caused by the electron population of ionic state and presents a power-law distribution. In the oxygen-poor environment, the fluorescence blinking of single molecules mainly stems from the electron population of triplet state and presents an exponential truncated power-law distribution. In the oxygen-specific environment, two kinds of electron transfer processes show an apparent competition effect, where part fluorescence blinking of single molecules follows a power-law distribution while the other part follows an exponential truncated power-law distribution..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 5, 53004 (2017)
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