Journals >Laser & Optoelectronics Progress
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2015
Volume: 52 Issue 3
35 Article(s)
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Fiber Optics and Optical Communications
Anti-Interference Relayed Link Method and Power Requirement Analysis for Ultraviolet Non-Line-of-Sight Communication
Li Jibo, Wu Xiaojun, Wang Hongxing, Li Bifeng, and Liu Chuanhui
To address the short distance transmission problem of ultraviolet communication for the power restriction with optical source device and the severe attenuation with atmospheric channel, an anti-interference relayed link method for ultraviolet non-line-of-sight communication is proposed. The relayed communication link iTo address the short distance transmission problem of ultraviolet communication for the power restriction with optical source device and the severe attenuation with atmospheric channel, an anti-interference relayed link method for ultraviolet non-line-of-sight communication is proposed. The relayed communication link is built in the transmission node from end point to end point by adopting multihop network mode structure, and the time division multiplexing technology is used to avoid possible interference from neighboring nodes distributed the different slots. At the same time, the power requirements of different communication styles both direct transmission information and relayed link retransmission information are analysed. The simulation analysis indicates that this method can decrease power for not only single node but also the system in the same transmission range, so the power utilization ratio is raised. Light weight nodes with low power consumption are shown to be feasible to implement and deploy..
Laser & Optoelectronics Progress
- Publication Date: Feb. 03, 2015
- Vol. 52, Issue 3, 30601 (2015)
Liquid Refractive Index Wireless Sensor Network Based on Long Period Fiber Grating and ZigBee
Shi Jia, Xu Degang, Yan Dexian, Xu Wei, and Yao Jianquan
A novel liquid refractive index (RI) wireless sensor network based on long period fiber gratings (LPFGs) and ZigBee is presented. The system includes sensor node, router node, coordinator and computer. In the sensor node, a kind of low-cost LPFG sensor based on the light intensity modulation is designed to measure liquA novel liquid refractive index (RI) wireless sensor network based on long period fiber gratings (LPFGs) and ZigBee is presented. The system includes sensor node, router node, coordinator and computer. In the sensor node, a kind of low-cost LPFG sensor based on the light intensity modulation is designed to measure liquid RI, which is made up with LPFGs and a special fabrication. At the same time, driver board of sensor is designed, which is made up with laser diode and photonic diode. Because of the nearly linear sides of loss peaks, the light power at one side of half of loss peak at fixed wavelength is measured to monitoring RI. A system is established by Zigbee, and realizes real- time, multi- point RI monitoring. NaCl solution, which has the RI range from 1.3347 to 1.3418, is measured. The resolution of RI is 0.0001, the maximum error of the sensor is 0.0004, and the average error is 0.00015. The system provides a new solution for applying optical fiber sensors to wireless network. It is convenient to set low- cost sensor network in large area and remove or add sensor nodes, and it has realized large-scale, multi-point, and high resolution environmental monitoring..
Laser & Optoelectronics Progress
- Publication Date: Feb. 02, 2015
- Vol. 52, Issue 3, 30602 (2015)
Research on Volume Scattering Phase Function under Ultraviolet Non-Line-of-Sight Single Scattering Link
He Hua
Based on ultraviolet single scattering link communication, the scattering particle is regarded as a differential volume, whose phase function after scattering is integrated under the correct scattering angles on the different positions within the effective scattering volume. Furthermore, the process is analyzed and forBased on ultraviolet single scattering link communication, the scattering particle is regarded as a differential volume, whose phase function after scattering is integrated under the correct scattering angles on the different positions within the effective scattering volume. Furthermore, the process is analyzed and formulas are deduced, which provide good support and solid foundation for ultraviolet communications..
Laser & Optoelectronics Progress
- Publication Date: Feb. 12, 2015
- Vol. 52, Issue 3, 30603 (2015)
Geometric Optics
Influence of Chromatic Aberration on Shack-Hartmann Wavefront Sensor
Xie Hongsheng, Yang Lebao, Li Dayu, Xuan Li, and Xia Mingliang
To obtain the high resolution retinal vessels imaging, illumination mode of double light sources is adopted in the retinal vessels adaptive optics (AO) imaging system. Because of the existence of ocular chromatic aberration in humans, the actual wavefront and the detected wavefront are inconsistent. Adopting 36 ZernikeTo obtain the high resolution retinal vessels imaging, illumination mode of double light sources is adopted in the retinal vessels adaptive optics (AO) imaging system. Because of the existence of ocular chromatic aberration in humans, the actual wavefront and the detected wavefront are inconsistent. Adopting 36 Zernike polynomials to fit the human eye′s wavefront, the research is done on the influence of chromatic aberration on Shack- Hartmann wavefront sensor (S- H WFS) using Liou & Brenann eye model, Navarro eye model and the vivo human eye: for Liou & Brenann and Navarro eye model, the chromatic aberration root mean square (RMS) of 561 nm and 785 nm is 0.09λ and 1.44λ respectively with defocus, and is 0.0025λ and 0.01λ without defocus. For the vivo human eye, the chromatic aberration RMS of 561 nm and 785 nm is 1.92λ with defocus, and is 0.04λ without defocus. According to Maréchal Criterion, the influence on the other chromatic aberrations is under diffractive limit level (1/14λ) excluding defocus. So the influence of chromatic aberration without defocus can be neglected. Defocus resulting from chromatic aberration can be compensated by moving imaging charge coupled device (CCD). According to the results, it is feasible to adopt double light sources to obtain the retinal vessels in AO imaging system..
Laser & Optoelectronics Progress
- Publication Date: Feb. 12, 2015
- Vol. 52, Issue 3, 30801 (2015)
Holography
Research on the Non Color Aliasing Real-Time Acquisition with Color Digital Holography Measurement
Yang Wenming, Song Qinghe, Zhang Yaping, Gui Jinbin, Lou Yuli, and Li Junchang
This paper presents a method for non color aliasing real-time color digital holographic interferometry based on Foveon CCD. The control mode of CCD is ameliorated and color aliasing is decreased consumedly. The influence on color hologram becomes very little. Experimental results confirm the suitability of the proposedThis paper presents a method for non color aliasing real-time color digital holographic interferometry based on Foveon CCD. The control mode of CCD is ameliorated and color aliasing is decreased consumedly. The influence on color hologram becomes very little. Experimental results confirm the suitability of the proposed method, where, color aliasing can be eliminated in phase difference detecting..
Laser & Optoelectronics Progress
- Publication Date: Jan. 19, 2015
- Vol. 52, Issue 3, 30901 (2015)
Image Processing
Face Image Recognition Method Based on the NSCT and Bionic Pattern
Zhou Liangji, Li Qingwu, Huo Guanying, and Zhu Guoqing
Concerning the low accuracy of classical face recognition algorithm，a face image recognition method based on the nonsubsampled Contourlet transform (NSCT) and bionic pattern is proposed. A face image is decomposed with NSCT and the decomposed coefficients are converted into energy features, then the face image is recogConcerning the low accuracy of classical face recognition algorithm，a face image recognition method based on the nonsubsampled Contourlet transform (NSCT) and bionic pattern is proposed. A face image is decomposed with NSCT and the decomposed coefficients are converted into energy features, then the face image is recognized by using the bionic pattern recognition algorithm. The UMIST，Yale and ORL face databases are used in the simulation experiment and two schemes- non- rejection and rejection are designed for the experiment. The experimental results show that compared with classical methods, the face image recognition method based on the NSCT and bionic pattern is superior to others, and the scheme of rejection shows a better comprehensive performance..
Laser & Optoelectronics Progress
- Publication Date: Jan. 29, 2015
- Vol. 52, Issue 3, 31001 (2015)
Window-Added Sampling for Improving Sparsity of Non-Sparse Representation of Signals
Yang Chuping, Cai Wenxi, and Weng Jiawen
In order to apply compressed sensing technique to a non-sparse signal in transform domains, a novel method is presented to improve the sparsity of the non-sparse representation of a signal. The method employs a movable window function to decompose the non-sparse representation of a signal in transform domains into multIn order to apply compressed sensing technique to a non-sparse signal in transform domains, a novel method is presented to improve the sparsity of the non-sparse representation of a signal. The method employs a movable window function to decompose the non-sparse representation of a signal in transform domains into multiple window-cutting representation, as long as the width of each window function is far less than the length of the signal, and then each window-cutting representation has good sparsity. The compressed sensing of nonsparse representation is realized by the sparse window-cutting representations. The detailed theoretical analysis using Gausian and rectangle window functions is presented and the experimental results of both noise-free image and noise-added image demonstrate that the method is valid..
Laser & Optoelectronics Progress
- Publication Date: Feb. 06, 2015
- Vol. 52, Issue 3, 31002 (2015)
Instrumentation, Measurement and Metrology
Study on Relationship Between Fringe Bandwidth and Wave-Front Slope in Interferometry
Meng Xiaochen, Hao Qun, and Zhu Lianqing
Interferometry is one of effective methods in measurement science. However, due to limited spatial band witdth of detection, it is difficult to increase the dynamic measurement range or to detect high frequency error of surface. The relationship among the spatial frequency and bandwidth of interference fringes and waveInterferometry is one of effective methods in measurement science. However, due to limited spatial band witdth of detection, it is difficult to increase the dynamic measurement range or to detect high frequency error of surface. The relationship among the spatial frequency and bandwidth of interference fringes and wavefront slope is analyzed and simulated based on the angular spectrum theory. The results show that the maximum slope of interference fringes corresponds to the maximum frequency, and the maximum dynamic range of interference detection can be determined by the wave- front slope, namely the bandwidth interference fringes can be estimated by wave- front slope. Conversely, according to the charge- coupled device (CCD) resolution, the total bandwidth of interference patterns can be determined, then the maximum wave- front slope can be obtained. That provides a theoretical quantitative basis for the spectrum characteristics of the interference methods and optimal allocation of bandwidth..
Laser & Optoelectronics Progress
- Publication Date: Feb. 06, 2015
- Vol. 52, Issue 3, 31201 (2015)
Research on Method to Measure Cotton Defects Based on Optoelectronic Technique
Zhang Zhifeng, Zhai Yusheng, Guo Yingying, Wang Xinjie, and Du Yinxiao
Cotton ginning quality is very important to evaluate the cotton grade. Cotton defects influence cotton and textiles qualities. It is very significant to measure cotton defects rapidly. Cotton defects include seed coat fragment, bearded motes, and ginned dead cotton which have different light response characteristics. ACotton ginning quality is very important to evaluate the cotton grade. Cotton defects influence cotton and textiles qualities. It is very significant to measure cotton defects rapidly. Cotton defects include seed coat fragment, bearded motes, and ginned dead cotton which have different light response characteristics. A novel method is proposed to measure the cotton defects based on optoelectronic measurement technique. The image segmentation is made by using adaptive thresholds and cotton defects can be inspected correctly. The best segmentation threshold of seed coat fragment and bearded motes is 0.6. The dead cotton′ s best segmentation threshold is 0.5. The comparison experimental results show that the inspection accuracy of measuring system is more than 85% and the measuring time is less than 3 seconds. The measuring system can meet requirement of cotton defects rapid inspection..
Laser & Optoelectronics Progress
- Publication Date: Jan. 29, 2015
- Vol. 52, Issue 3, 31202 (2015)
Position and Attitude Measurement Method Based on Unmanned Aerial Vehicle Image Feature Fusion
Xu Yong, and Jia Tao
A new position and attitude measurement method based on unmanned aerial vehicle (UAV) image feature fusion and measurement system are proposed to precisely measure the position and attitude of UAV. To work out the position and attitude parameters of UAV, we take full advantage of the extracted robust corners, wing lineA new position and attitude measurement method based on unmanned aerial vehicle (UAV) image feature fusion and measurement system are proposed to precisely measure the position and attitude of UAV. To work out the position and attitude parameters of UAV, we take full advantage of the extracted robust corners, wing lines and symmetric axis of UAV. We compute the coordinates of corners by lines intersection, using least squares (LS) method. We find the unit direction vectors of wing lines and axis of symmetry by singular value decomposition method. Considering the corners wing lines and symmetric axis simultaneously, we get the position and attitude of UAV by the proposed feature fusion method. Numeric simulation results show that the precision of position less than 0.05 m and the precision of attitude less than 0.5°, when the measurement system contains two cameras, standard deviation of noise is 1 and the distance of UAV is approximately 1200 m. What′s more, increasing the number of network cameras helps to improve the measurement accuracy. Precision comparison proofs the correctness, feasibility and high precision of the proposed feature fusion method..
Laser & Optoelectronics Progress
- Publication Date: Jan. 19, 2015
- Vol. 52, Issue 3, 31203 (2015)
Windowed Fourier Transform Filter Method with Improved Threshold
Cai Changqing, and Zhang Yongshan
Fixed threshold algorithm can achieve better denoising effect due to the small spectral coefficients caused by noise being set to zero. But because of its threshold function is not continuous and a mutation in the vicinity of the threshold, so some big noise spectral coefficients′ reservations and small spectral coeffiFixed threshold algorithm can achieve better denoising effect due to the small spectral coefficients caused by noise being set to zero. But because of its threshold function is not continuous and a mutation in the vicinity of the threshold, so some big noise spectral coefficients′ reservations and small spectral coefficients result in the loss of information. In order to improve filtering algorithm threshold for windowed Fourier transform method, an adaptive threshold method is proposed. Through the verification of simulated speckle pattern interferometer phase map, the adaptive threshold method can effectively filter out the noise with the signal information well retained..
Laser & Optoelectronics Progress
- Publication Date: Feb. 02, 2015
- Vol. 52, Issue 3, 31204 (2015)
Lenses Axial Space Measurement by Laser Confocal Technology
Zhao Weiqian, Shen Yang, Qiu Lirong, and Yang Jiamiao
The axial space between lenses is an important parameter for the assembling of lenses. In order to achieve the precise measurement of the lenses axial space, a laser confocal lenses axial space measurement (LCASM) is proposed. Using the character that the peak point of confocal response curve correspond to the focus ofThe axial space between lenses is an important parameter for the assembling of lenses. In order to achieve the precise measurement of the lenses axial space, a laser confocal lenses axial space measurement (LCASM) is proposed. Using the character that the peak point of confocal response curve correspond to the focus of system objective, LCASM utilizes the annular laser confocal chromatography focusing technique (ACFT) to precisely identify the vertex position of an assembled lenses on the inner-and-outer spherical surface, then uses the ray tracing facet iterative algorithm to precisely determine the vertex position, and thereby obtaining the lenses axial space. The preliminary experiments indicate that LCASM has measurement repeatability of 0.3 μm..
Laser & Optoelectronics Progress
- Publication Date: Feb. 12, 2015
- Vol. 52, Issue 3, 31205 (2015)
Lasers and Laser Optics
Influence of Laser Spot Diameter on Cladding Layer Cracking
Fu Fuxing, Chang Gengrong, Zhao Xiaoxia, and Zhang Yanli
The physical mechanism of crack formation in the process of laser cladding is analysed by theoretical derivation and the influence of laser spot diameter on crack defect is researched. The powder of Ni60 is cladded on the surface of base material (40Cr) by experiment and the characteristic of crack is analysed by obserThe physical mechanism of crack formation in the process of laser cladding is analysed by theoretical derivation and the influence of laser spot diameter on crack defect is researched. The powder of Ni60 is cladded on the surface of base material (40Cr) by experiment and the characteristic of crack is analysed by observing the distributions of crack with optical microscope. The results show that the crack ratio of laser cladding layer is increasing gradually with the increase of spot diameter, in addition, the depth and width of crack are increasing obviously..
Laser & Optoelectronics Progress
- Publication Date: Jan. 29, 2015
- Vol. 52, Issue 3, 31401 (2015)
Realization of Narrow Linewidth 776 nm Laser and Its Impact on Rubidium Vapor Lasers
Zuo Lei, Hua Weihong, Yang Zining, Wang Hongyan, and Xu Xiaojun
Diode-pumped alkali vapor laser (DPAL) is a candidate in high power laser field. Under conditions of high-power pumping, ionization process will occur in DPAL′s gain medium, which has a negative impact on laser performance. One of the main rubidium atomic ionization channel is cascaded effect (5S→5P→5D) induced by the Diode-pumped alkali vapor laser (DPAL) is a candidate in high power laser field. Under conditions of high-power pumping, ionization process will occur in DPAL′s gain medium, which has a negative impact on laser performance. One of the main rubidium atomic ionization channel is cascaded effect (5S→5P→5D) induced by the 776 nm far wing spectral component of the 780 nm diode pump source. In order to quantitatively measure the degree of ionization of rubidium DPAL, frequency-narrowed 776 nm high power semiconductor light source is needed to simulate the far wing of 780 nm pump light. Based on Littrow configuration, a linenarrowed 776 nm semiconductor laser output is realized, with spectral linewidth of less than 0.15 nm, output power of more than 10 W, and external cavity efficiency of 67%. By using 780 nm and 776 nm cascade pumping, a significant enhancement of fluorescence signal has been observed..
Laser & Optoelectronics Progress
- Publication Date: Feb. 06, 2015
- Vol. 52, Issue 3, 31402 (2015)
Fabrication Process Study of Silicon Nitride Passivation Layer on GaAs Substrate at Low Temperature
Wu Tao, and Jiang Xianfeng
In order to obtain the excellent silicon nitride (SiN) films in AlGaAs laser, SiN films with different deposition parameters are fabricated on GaAs substrate by plasma enhanced chemical vapor deposition (PECVD) at low temperature. The residual stress, surface morphology and refractive index of these films are investigaIn order to obtain the excellent silicon nitride (SiN) films in AlGaAs laser, SiN films with different deposition parameters are fabricated on GaAs substrate by plasma enhanced chemical vapor deposition (PECVD) at low temperature. The residual stress, surface morphology and refractive index of these films are investigated comprehensively by means of refractometer, atomic force microscope (AFM) and Fourier transform infrared spectroscopy (FTIR). The results show that residual stress of SiN films increases with the deposition power. An ultra low stress (6 MPa) is obtained at the pressure of 200 Pa. The AFM results show that the surface roughness increases with the deposition power, while decreases with the deposition pressure. Both the deposition power and the pressure have a weak effect on the refractive index. The refractive index of all these films are 2.0~2.2. The FTIR results show that the H element exists in the film with the N-H bond. SiN films with ultra low stress and good surface morphology can be obtained by selecting proper power and pressure at low temperature..
Laser & Optoelectronics Progress
- Publication Date: Jan. 29, 2015
- Vol. 52, Issue 3, 31403 (2015)
Narrow Linewidth Diode Laser with Grating External Cavity in 405 nm Band
Li Bin, Tu Pin, Xu Yongyue, Li Zhe, Yu Anlan, Wang Xinbing, and Zuo Duluo
Free-running diode lasers cannot meet the demands for the line width in the applications due to their broad line width such as Raman scattering and so on. Therefore, it is quite necessary to develop diode lasers with narrow line width, steady wavelength. A reflective holographic grating is taken as a line width narrowiFree-running diode lasers cannot meet the demands for the line width in the applications due to their broad line width such as Raman scattering and so on. Therefore, it is quite necessary to develop diode lasers with narrow line width, steady wavelength. A reflective holographic grating is taken as a line width narrowing component, and a 405 nm diode laser with external cavity in Littrow configuration is studied. As the introduction of the reflective holographic grating, a coupled external cavity is built between the surface of the grating and the emitting surface of the diode laser, and it improved the line width performance of 450 nm diode laser to a large extent. The experiment results show that, by adding the 2400 line/mm reflective holographic grating, the threshold current of the diode laser is reduced from 31 mA to 22 mA, and line width is reduced form 1 nm to 0.03 nm of free-running, and narrow line width output is realized. A 28 mW output power of the narrow line width laser is got at 100 mA which is 31.7 percent to the power of the free-running diode laser. Besides, by changing the angle of the reflective holographic grating, continuous wavelength tuning of 3.5 nm is realized in a large tuning range of injection current..
Laser & Optoelectronics Progress
- Publication Date: Feb. 02, 2015
- Vol. 52, Issue 3, 31404 (2015)
Machine Vision
Wood Knot Defects Recognition with Gray-Scale Histogram Features
Song Xiaoyan, Bai Fuzhong, Wu Jianxin, Chen Xiaodong, and Zhang Tieying
The knot on the wood surface is a very important kind of wood defects, and it is the key specification for assessing the appearance grade and the quality of lumber and veneer. To enhance the accuracy and efficiency of knot defects recognition, and improve the automatic level of detecting procedure, the recognition of kThe knot on the wood surface is a very important kind of wood defects, and it is the key specification for assessing the appearance grade and the quality of lumber and veneer. To enhance the accuracy and efficiency of knot defects recognition, and improve the automatic level of detecting procedure, the recognition of knot defects by using the statistics features of gray-scale histogram from wood surface image is studied. The classifying ability of seven statistics features is evaluated through using the between-cluster distance, and hence the optimal statistics feature that recognizes the knot defect is determined, such as the smoothness. At the same time, an adaptive clustering method with maximal between-cluster variance is presented to determine the classifying threshold, and then based on that the knot defect is recognized. The online detection experiment shows that the recognition rate of the presented method is up to 99%..
Laser & Optoelectronics Progress
- Publication Date: Jan. 29, 2015
- Vol. 52, Issue 3, 31501 (2015)
Materials
Study on Numerical Calculation Models for Solid-Liquid Two-Phase Impinging Jet with Nanoparticles
Ma Yinghui, Jiang Fang, and Xu Xuefeng
Based on Fluent which is a computational fluid dynamics (CFD) analysis software, a new hybrid multiphase flow model is proposed based on the equivalent viscosity for the solid- liquid two- phase containing nanoparticles impinging jet flow, and it is compared with the discrete phase model (DPM) considering interactions Based on Fluent which is a computational fluid dynamics (CFD) analysis software, a new hybrid multiphase flow model is proposed based on the equivalent viscosity for the solid- liquid two- phase containing nanoparticles impinging jet flow, and it is compared with the discrete phase model (DPM) considering interactions and no interaction. It demonstrates the comparative analysis of the calculations of three models under different solid concentrations, and meanwhile, illustrates the effects that three models have on, in terms of radial velocity, axial velocity and dynamic pressure of the work-plane, and outlet velocity of the nozzle as well as dynamic pressure and velocity of the axis, thus providing the scope of application of the three models. The research results show that when the volume fraction of nanoparticle is less than 10%, the model with equivalent viscosity, which replaces the DPM without the consideration of interaction, can be used for calculation. Finally appropriate computational model is proposed based on the scope of deviation rate..
Laser & Optoelectronics Progress
- Publication Date: Jan. 23, 2015
- Vol. 52, Issue 3, 31601 (2015)
Optical Characteristics of One-Dimensional Photonic Crystals with Two Element Compound Defect Layers
He Jie, Song Litao, Guo Tao, Liu Xiuying, Yang Wu, and Liu Kun
The optical characteristics of one-dimensional photonic crystals with two element compound defect layers is studied by transfer matrix method．The process and optical characteristics, which changed from one-dimensional photonic crystals with two element compound defect layers to one-dimensional compound photonic crystalThe optical characteristics of one-dimensional photonic crystals with two element compound defect layers is studied by transfer matrix method．The process and optical characteristics, which changed from one-dimensional photonic crystals with two element compound defect layers to one-dimensional compound photonic crystals, are mainly discussed. The results indicate that the defect mode and its wavelength can be controlled by the number of layers and structures of the two element compound defects. Thereby it can be realized that optical narrowband filter with high quality or bandgap extension. The results can provide reference for the design of one-dimensional photonic crystals micro cavity with two element compound defect layers, which can be used for making filter, laser, etc..
Laser & Optoelectronics Progress
- Publication Date: Jan. 29, 2015
- Vol. 52, Issue 3, 31602 (2015)
Medical Optics and Biotechnology
Optical Signal Detection and Processing System for WBC Five Classification
Wan Lixia, Long Wei, Zhang Xingyuan, and Lu Bin
There are many white blood cell (WBC) classification methods in the research and development field of five classification blood analyzer and their functions are relatively perfect, but the majority of instrument structure is complex, and has more interference factors, and thus their stability and precision can not be gThere are many white blood cell (WBC) classification methods in the research and development field of five classification blood analyzer and their functions are relatively perfect, but the majority of instrument structure is complex, and has more interference factors, and thus their stability and precision can not be guaranteed as a result. Therefore, an optical signal detection and processing system that is applied to the WBC five classification and uses the full-optical detection technology is proposed, taking the front side light scattering (FSC) and axial light absorption (ALL) as characteristics of cells, the photoelectric conversion circuit, filter and amplification circuit and analog/digital (A/D) conversion circuit are designed, and the five classification of WBC is completed. The blood analyzer using this system has the advantages of simple structure and high reliability. The test results show that the correlation r of the system for WBC classification is good, and the precision of the instrument is closed to Mythic 22, which is a high-grade five classification blood cell analyzer, and the function and performance of the instrument is perfect..
Laser & Optoelectronics Progress
- Publication Date: Feb. 10, 2015
- Vol. 52, Issue 3, 31701 (2015)
Microscopy
Focusing of High Numerical Aperture Azimuthally Polarized Beams
Xiao Yun, Zhang Yunhai, Yang Haomin, and Tan Huiming
According to Wolf and Richard′s vectorial diffraction integral, a model is established and the focusing spots are analyzed to study the focusing of the azimuthally polarized beams and improve the resolution of laser scanning confocal microscope (LSCM). The azimuthally polarized beams focus into a hollow spot, but it beAccording to Wolf and Richard′s vectorial diffraction integral, a model is established and the focusing spots are analyzed to study the focusing of the azimuthally polarized beams and improve the resolution of laser scanning confocal microscope (LSCM). The azimuthally polarized beams focus into a hollow spot, but it becomes into a solid spot after 0~2 π phase modulation. The full-width at half-maximum (FWHM) of the azimuthally polarized spot after 0~2 π phase modulation is 17.6% smaller than that of the radially polarized spot, and is 11.6% smaller than that of the circular polarized spot. The azimuthally polarized spot after 0~2 π phase modulation which has a smaller focusing spot can improve the resolution for LSCM..
Laser & Optoelectronics Progress
- Publication Date: Jan. 29, 2015
- Vol. 52, Issue 3, 31801 (2015)
Nonlinear Optics
Positive Electron Acceleration in Sine Triangulation Plasma under Compton Scattering
Zhang Kaiping, Mao Jianjing, and Hao Dongshan
By using the model of multi-photon nonlinear Compton scattering and numerical simulating method, the positive electron acceleration in the wake field of the sine triangulation extra- intense laser- plasma is studied, a new mechanism on the positive electron acceleration in the plasma wake field produced by the incidentBy using the model of multi-photon nonlinear Compton scattering and numerical simulating method, the positive electron acceleration in the wake field of the sine triangulation extra- intense laser- plasma is studied, a new mechanism on the positive electron acceleration in the plasma wake field produced by the incident extra- intense laser and nonlinear Compton scattered light is given, and the revised formula and numberical simulation results on the positive electron acceleration energy are given out. The results show that the acceleration effect on the plasma wake field of the extra-intense laser pulse of non-symmetry sine triangle to the positive electron is better than the plasma wake field of the extra- intense laser pulse of symmetry sine triangle, the width of the coupling laser pulse of the non- symmetry sine triangle and the ratio of the pulse increasing length and decreasing length is decreased by Compton scattering, and the acceleration energy of the positive electron is clearly increased. The causes that acceleration energy in the laser propagation direction of the positive electron is increased are that the positive electron frequency increases, the anisotropic distribution of the transverse speed of the positive electron is increased and the acceleration energy in the transverse direction of the positive electron is limited by the wake field..
Laser & Optoelectronics Progress
- Publication Date: Feb. 06, 2015
- Vol. 52, Issue 3, 31901 (2015)
Reviews
Research Progress of Infrared Supercontinuum Generation in Chalcogenide Glass Fibers
Wang Cui, Dai Shixun, Zhang Peiqing, Zhang Bin, Wang Xunsi, Shen Xiang, Hou Jing, Wang Rongping, and Tao Guangming
Chalcogenide glasses have a very wide range of infrared transmittance, extremely high linear and nonlinear refractive index. Recently, infrared supercontinuum (SC) generation in chalcogenide glass fibers attracts extensive attentions for its potential applications in sensing, security and defense. In this article, the Chalcogenide glasses have a very wide range of infrared transmittance, extremely high linear and nonlinear refractive index. Recently, infrared supercontinuum (SC) generation in chalcogenide glass fibers attracts extensive attentions for its potential applications in sensing, security and defense. In this article, the research progress of infrared SC generation in chalcogenide glass fibers is reviewed, including the SC generation of chalcogenide tapered fiber and microstructured fibers, and the new fiber structure design for SC generation. Moreover, current problems in exploring SC generation are summarized, and their potential applications are discussed..
Laser & Optoelectronics Progress
- Publication Date: Feb. 12, 2015
- Vol. 52, Issue 3, 30001 (2015)
Progress of Single Mode Propagation Technology in Large Mode Area Fiber
Zhao Nan, and Li Jinyan
Due to nonlinear effects and optical damage which limit the power promotion of fiber lasers, large mode area fiber with single mode propagation has aroused wide public interest over recent years. The latest progress of single mode output technology in large mode area fiber is introduced from three aspects including fibDue to nonlinear effects and optical damage which limit the power promotion of fiber lasers, large mode area fiber with single mode propagation has aroused wide public interest over recent years. The latest progress of single mode output technology in large mode area fiber is introduced from three aspects including fiber modes filtering, structure design and modes conversion. The development trends of high power fiber lasers are also prospected by comparing these methods..
Laser & Optoelectronics Progress
- Publication Date: Feb. 02, 2015
- Vol. 52, Issue 3, 30002 (2015)
Present Status of Impurity Free Vacancy Disordering Research and Application
Lin Tao, Sun Hang, Zhang Haoqing, Lin Nan, Ma Xiaoyu, and Wang Yonggang
With the discovery of quantum well intermixing (QWI), it has made tremendous progress over the past few years. Among all the approaches of QWI, meticulous researches and wide range of applications are acquired in impurity free vacancy disordering (IFVD) owing to its unique merits. Present status of IFVD research and apWith the discovery of quantum well intermixing (QWI), it has made tremendous progress over the past few years. Among all the approaches of QWI, meticulous researches and wide range of applications are acquired in impurity free vacancy disordering (IFVD) owing to its unique merits. Present status of IFVD research and application is comprehensively analyzed from the aspect of theory, dielectric films, materials, quantum dots and applications..
Laser & Optoelectronics Progress
- Publication Date: Jan. 29, 2015
- Vol. 52, Issue 3, 30003 (2015)
Process in Erbium-Doped Chalcogenide Waveguide of Optical Communications
Li Shuang, Qi Lei, Wang Guoxiang, Li Jun, Shen Xiang, Xu Peipeng, Dai Shixun, Nie Qiuhua, and Xu Tiefeng
An overview of the erbium- doped chalcogenide glass for its material properties and developmental prospects in waveguide is provided, Meanwhile, the description of the structure design and gain characteristics of erbium-doped chalcogenide waveguide is presented. A summary of the problems existing in the current study iAn overview of the erbium- doped chalcogenide glass for its material properties and developmental prospects in waveguide is provided, Meanwhile, the description of the structure design and gain characteristics of erbium-doped chalcogenide waveguide is presented. A summary of the problems existing in the current study is made, and a prospect of the further research in erbium-doped chalcogenide waveguide is propesed..
Laser & Optoelectronics Progress
- Publication Date: Feb. 02, 2015
- Vol. 52, Issue 3, 30004 (2015)
Research Progress in Optoelectronic Reservoir Computing System
Bao Xiurong
The reservoir computing is an efficient method of bionics research for processing time signal. The framework of reservoir computing is consists of nonlinear periodic dynamic system, the input layer and the output layer. There are many kinds of possible implementation methods for reservoir computing. The optoelectronic The reservoir computing is an efficient method of bionics research for processing time signal. The framework of reservoir computing is consists of nonlinear periodic dynamic system, the input layer and the output layer. There are many kinds of possible implementation methods for reservoir computing. The optoelectronic reservoir based on a single nonlinear node plus delay feedback line is introduced mainly. The working principle of reservoir, the model of optoelectronic reservoir and the latest research progress of analog input layer and analog output layer are introduced, the future research trend of optoelectronic reservoir is discussed..
Laser & Optoelectronics Progress
- Publication Date: Jan. 23, 2015
- Vol. 52, Issue 3, 30005 (2015)
Research Status and Development Trends of Fiber Optical Technology for Water Quality Monitoring
Chen Hao, Liu Yueming, Zou Jianyu, Xia Zhongcheng, and Gao Xiaoliang
Based on the current optical fiber sensing technology, the study and applications of optical fiber sensing technology under different optical principles of water quality monitoring, such as the Hydrogen ion concentration (pH) value, chemical oxygen demand (COD), dissolved oxygen and heavy metal ion contaminants, are prBased on the current optical fiber sensing technology, the study and applications of optical fiber sensing technology under different optical principles of water quality monitoring, such as the Hydrogen ion concentration (pH) value, chemical oxygen demand (COD), dissolved oxygen and heavy metal ion contaminants, are presented. The research status of the past 10 years as well as the advantages and disadvantages of fiber optical technology for water quality monitoring based on different principles is described. At last, the development trends of fiber optical technology for water quality are analyzed and forecasted, which provides the technical ideas for the further water quality monitoring..
Laser & Optoelectronics Progress
- Publication Date: Feb. 02, 2015
- Vol. 52, Issue 3, 30006 (2015)
Progress in Laser Ignition Based on Passively Q-Switched Solid-State Lasers
Yang Lin, and Dong Jun
Laser ignition technology emerges as an advanced combustion method for engine. It can make the engine reduce waste gas emission and improve the thermal effect. Lean burning improves thermal efficiency and reduces exhaust emissions by laser ignition. In recent decades, short pulse, high peak power passively Q-switched sLaser ignition technology emerges as an advanced combustion method for engine. It can make the engine reduce waste gas emission and improve the thermal effect. Lean burning improves thermal efficiency and reduces exhaust emissions by laser ignition. In recent decades, short pulse, high peak power passively Q-switched solid-state lasers are developed rapidly for their potential applications in laser ignition. Especially the passively Q-switched lasers using neodymium ion (Nd3+) or ytterbium ion (Yb3+) doped materials as the laser gain media and Cr4+∶YAG as the saturable absorber, make much progress in potential laser ignition applications. We overviewe the mechanism of laser ignition and progresses in passively Q-switched solid-state lasers based on Nd∶YAG/Cr4+∶YAG and Yb∶YAG/Cr4+∶YAG. And the advantages and disadvantages of these two types passively Q-switched lasers used in laser ignition are discussed systematically. The advantages of Yb∶YAG/Cr4+∶YAG passively Q-switched microchip lasers used in laser ignition are addressed for future application in engine ignition. And the key issues for developing high peak power Yb∶YAG/Cr4+∶YAG passively Q-switched microchip lasers are also addressed..
Laser & Optoelectronics Progress
- Publication Date: Feb. 02, 2015
- Vol. 52, Issue 3, 30007 (2015)
Research Progress of the Generation Methods of Airy Beam
Cheng Zhen, Zhao Shanghong, Chu Xingchun, Deng Boyu, and Zhang Xiwen
Airy beam has gained a widespread atlention owing to its particular properties: approximate nondiffraction, self-accelerating in the transverse and self-recovery as a member of non-diffraction light family. Airy beam has a broad application prospect in optoelectronic sciences, particle manipulation, atmospheric communiAiry beam has gained a widespread atlention owing to its particular properties: approximate nondiffraction, self-accelerating in the transverse and self-recovery as a member of non-diffraction light family. Airy beam has a broad application prospect in optoelectronic sciences, particle manipulation, atmospheric communication and so on. The main methods of Airy beam generation are summarized and a deep analysis for each method is made from the cost of the system, how complex to come true and potential of applications, and some improving and perfecting suggestions are given..
Laser & Optoelectronics Progress
- Publication Date: Feb. 06, 2015
- Vol. 52, Issue 3, 30008 (2015)
Visual Discomfort Induced by Three-Dimensional Display Technology
Li Jing, Wang Ani, Wang Junle, Marcus Barkowsky, and Patrick Le
At present, three-dimensional (3D) display technology is attracting considerable attention. However, the added binocular depth introduced by stereoscopic 3D technology may not only provide viewers with an entirely different and enhanced viewing experience, but also with visual discomfort and visual fatigue. These problAt present, three-dimensional (3D) display technology is attracting considerable attention. However, the added binocular depth introduced by stereoscopic 3D technology may not only provide viewers with an entirely different and enhanced viewing experience, but also with visual discomfort and visual fatigue. These problems, besides being related to the health and safety of viewers, have recently gained increasing attention because they significantly impede viewing experience. State-of-the-art studies on visual discomfort related to three-dimensional television (3DTV) are introduced. These studies include those on 3D display technology, the main causes of visual discomfort, subjective assessment measurement methods, and objective psychophysical prediction. This work is relevant to the industry as it suggest ways to prevent visual discomfort when producing 3D displays or shooting 3D videos..
Laser & Optoelectronics Progress
- Publication Date: Feb. 12, 2015
- Vol. 52, Issue 3, 30009 (2015)
Research and Progress of All-Fiber Single-Longitudinal Mode Lasers Based on Fiber Grating Technologies
Xu Ou
The key technologies of achieving single-frequency fiber lasers are how to enable the resonant cavities to have the high selectivity of modes, and how to properly use the narrow-width filters to help selecting modes. In addition, the fiber grating technology play an important role in the designing and optimizing fiber The key technologies of achieving single-frequency fiber lasers are how to enable the resonant cavities to have the high selectivity of modes, and how to properly use the narrow-width filters to help selecting modes. In addition, the fiber grating technology play an important role in the designing and optimizing fiber lasers. The main technologies and methods reported recently about the single or multiple wavelength single-frequency fiber lasers based on fiber gratings are summarized, their merits, demerits are analyzed and the developments are prospected..
Laser & Optoelectronics Progress
- Publication Date: Feb. 05, 2015
- Vol. 52, Issue 3, 30010 (2015)
Scattering
Particle Size Distribution Measurement by Recursion Nonnegative Phillips-Twomey Analytical Method with Multiangle Dynamic Light Scattering
Li Lei, Yang Kecheng, Wang Wanyan, Xia Min, and Li Wei
Besides the advantages such as the fast response speed, non-contact measurement and so on, the multiangle dynamic light scattering (MDLS) can give better particle-size distribution (PSD) because it can get more information about scattering light compared to single-angle light scattering technolgy, which can reflect theBesides the advantages such as the fast response speed, non-contact measurement and so on, the multiangle dynamic light scattering (MDLS) can give better particle-size distribution (PSD) because it can get more information about scattering light compared to single-angle light scattering technolgy, which can reflect the characteristic parameters of particles, and the improvement of the accuracy of MDLS depends largely on appropriate PSD inversion methods. Based on Phillips-Twomey (PT) algorithm, the Recursion Nonnegative Phillips-Twomey (RNNPT) algorithm is proposed, which uses the MR-L-curve to estimate the regularization parameter, recursion algorithm to obtain the weighting coefficients and the addition of the nonnegative constraint. Through the exact determination of the weighting coefficients, RNNPT algorithm can improve the accuracy of MDLS PSD inversion algorithm. When the light intensity autocorrelation function noise range is from 0.01% to 1%, the results show that the inverted PSDs of the two unimodal distribution and the bimodal distribution are comparatively desired with the noise level under 0.1%. In contrast to recursion Phillips-Twomey (RPT) and the existing recursion Tikhonov (RT) algorithm, the calculation results show that the weighting coefficient ratio obtained from RNNPT algorithm is minimum and the inverted PSD is closest to the theoretical one..
Laser & Optoelectronics Progress
- Publication Date: Feb. 10, 2015
- Vol. 52, Issue 3, 32901 (2015)
Spectroscopy
Discrimination Analysis of Adulterating Olive Oil with Soybean Oil by Attenuated Total Reflectance-Fourier Transform Infrared Spectrometry Combined with Pattern Recognition Methods
Li Yuanpeng, Huang Furong, Xian Ruiyi, Xia Kaiyue, Wang Yong, and Chen Xingdan
Attenuated total reflectance-Fourier transform infrared spectroscopy (FTIR-ATR) combined with pattern recognition is applied to establish a rapid discrimination model of olive oil. Measurements of FTIR-ATR spectra of pure olive oil samples and pure soybean oil samples from different brands and mixed samples of pure oliAttenuated total reflectance-Fourier transform infrared spectroscopy (FTIR-ATR) combined with pattern recognition is applied to establish a rapid discrimination model of olive oil. Measurements of FTIR-ATR spectra of pure olive oil samples and pure soybean oil samples from different brands and mixed samples of pure olive oil doped with soybean oil are performed. The obtained spectra between 625 cm-1 and 4000 cm-1 are regarded as the research object of discrimination analysis. The principal component analysis (PCA) is applied to the dimension reduction of these spectra. Identification of the pure olive oil samples, pure soybean oil samples and three samples of olive oil doped with soybean oil is carried out by two pattern recognition methods, the Fisher discrimination and multilayer perception neural network. The experiment results show that the identification effect after the wavelet denoising is the best among all the adopted pretreatment methods. The original discriminant accuracy of discrimination model established by PCA combined with Fisher discriminant analysis reaches 100%. The cross validation accuracy reaches 97.1%. Classification accuracy of the training set and the test set by multilayer perception neural network identification model is 100% . Therefore, FTIR-ATR spectroscopy combined with pattern recognition method can realize the identification of the pure olive oil samples, pure soybean oil samples and three different oil blend samples. This method has some advantages over other methods owing to its easy operation, high speed and reliability..
Laser & Optoelectronics Progress
- Publication Date: Feb. 10, 2015
- Vol. 52, Issue 3, 33001 (2015)
Effective Reflection Luminance of Object under Light Source
Yao Qi, and Gu Beibei
The effective reflection luminance of different color temperature (CT) blackbody radiation light sources on warm- toned and cold- toned samples and different dominant wavelength (DW) Gaussian light sources on samples with destined DW are studied. How different CT and DW of light sources work on reflection luminance areThe effective reflection luminance of different color temperature (CT) blackbody radiation light sources on warm- toned and cold- toned samples and different dominant wavelength (DW) Gaussian light sources on samples with destined DW are studied. How different CT and DW of light sources work on reflection luminance are obtained. Results show that matched CT of light source and object lead to higher effective reflection luminance, and matched DW of light source and object also lead to higher effective reflection luminance. In multi- chips light emitting diode (LED) spectrum synthesis, matched DW can achieve relatively higher effective refiection luminance and is the key importance of improving effective efficiency, and color appearance of light source should also be taken in consideration. RGB chip LEDs with high purity single chip are more likely to reach high luminivity reflectivity for a designated object. Because of white chip has a low purity, WRB chip LEDs are more stable in luminance reflectivity for all kinds of objects..
Laser & Optoelectronics Progress
- Publication Date: Feb. 05, 2015
- Vol. 52, Issue 3, 33002 (2015)
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