Journals >Chinese Journal of Lasers
Contents
2016
Volume: 43 Issue 5
37 Article(s)
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Biomedical Photonics and Laser Medicine
Intrinsic Tissue Fluorescence Spectrum Recovery Based on Particle Swarm Optimization Algorithm
Zhang Yuanzhi, Liu Yong, Hou Huayi, Zhu Ling, Wang An, and Wang Yikun
In order to reduce the influence of absorption and scattering on tissue fluorescence spectra, the tissue fluorescence and diffuse reflection are simulated under different optical parameters with the Monte Carlo (MC) method, and a fluorescence recovery algorithm based on the tissue diffuse reflection spectrum is proposeIn order to reduce the influence of absorption and scattering on tissue fluorescence spectra, the tissue fluorescence and diffuse reflection are simulated under different optical parameters with the Monte Carlo (MC) method, and a fluorescence recovery algorithm based on the tissue diffuse reflection spectrum is proposed. The empirical parameters in the proposed algorithm are coded as a particle in the solution domain, the classification performance is defined as fitness, and then a particle swarm optimization (PSO) algorithm is established to optimize empirical parameters. Skin fluorescence and diffuse reflection spectra of 327 subjects are collected with a tissue detection system for noninvasive screening of diabetes. The fluorescence spectra are recovered by the empirical approach, and the fluorescence intensity before and after recovery is selected as the input variable for the receiver operating characteristic (ROC) curve analysis, which is applied to evaluating the classification performance in diabetes screening. The sensitivity and specificity are 32% and 76% respectively, and the area under the ROC curve is 0.54 when the spectra before recovery are used, while the sensitivity and specificity are 72% and 86% respectively, and the area under the ROC curve is 0.86 when the spectra after recovery are used. The results indicate that using the tissue fluorescence spectrum recovery algorithm based on PSO can improve the application of tissue fluorescence spectroscopy effectively..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 504001 (2016)
Laser Manufacturing
Laser Repairing Process of V-Groove in Single-Crystal Superalloy
Luo Deng, Lu Yuanyuan, Guo Xixi, Du Jinzheng, and Liu Dejian
The effect of laser repairing process of single-crystal superalloy on the dendrites growth, and the effect of bottom angle of V-groove on the dendrites growth are analyzed. The proper process is determined through laser cladding on the DD5 sample, and it is revealed that the decrease of heat input is beneficial to broaThe effect of laser repairing process of single-crystal superalloy on the dendrites growth, and the effect of bottom angle of V-groove on the dendrites growth are analyzed. The proper process is determined through laser cladding on the DD5 sample, and it is revealed that the decrease of heat input is beneficial to broaden the zone of directional dendrites. By overlapping experiment on the DD5 sample, it is found that the overlapping rate of 30% benefits the consistency of the dendrites growth in cladding region. With appropriate process parameters, V-grooves of different bottom angles in the DD6 sample are repaired. The results show that changes in the bottom angle of the V-groove from 60° to 120° have little effect on the dendrites growth direction at the bottom. The number of stray grains near the side wall decreases as the angle between the direction of molten pool temperature gradient and the optimal growth direction increases. The stray grains are eliminated in the region of side wall when the bottom angle is 120°..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503001 (2016)
Laser-Arc Hybrid Welding of Titanium Alloy and Stainless Steel with Copper Interlayer
Wang Hongyang, Li Quan, Song Gang, and Liu Liming
The TC4 titanium alloy and 304 stainless steel are welded by laser-arc hybrid heat source with copper interlayer. Macrostructure and microstructure of cross sections, main compositions, mechanical properties and fracture positions of welding joints are examined. The results show that the transition zone is characterizeThe TC4 titanium alloy and 304 stainless steel are welded by laser-arc hybrid heat source with copper interlayer. Macrostructure and microstructure of cross sections, main compositions, mechanical properties and fracture positions of welding joints are examined. The results show that the transition zone is characterized by Ti-Cu intermetallic, solid solution of copper, and Fe-Cu eutectic mixture. With the increase of laser power, the thickness of Ti-Cu intermetallic near the Ti-Cu interface increases, which has harmful effect on mechanical properties. Fracture of joint mainly happens at the interface between titanium alloy and copper when laser power is higher. The mutual diffusion depth and density of elements, such as copper and iron near the interface between copper and stainless steel, also increase, which is beneficial to enhancing mechanical properties. Fracture of joint mainly happens at the interface between the copper and stainless steel when laser power is lower. The key point to achieve favorite welding joint is the control of Ti-Cu intermetallic and Fe-Cu eutectic mixture..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503002 (2016)
Study of Laser-Driven Shock Wave Propagation in Film-Substrate Structure Material
Ye Yunxia, Zhao Shuyi, and Zuo Hui
In order to study laser-induced shock wave′s propagation properties in the film-substrate structure material and its impact on film-substrate bonding strength, the process is studied systematically based on Abaquas software and experiments. In the numerical simulation, the film-substrate structure models with differentIn order to study laser-induced shock wave′s propagation properties in the film-substrate structure material and its impact on film-substrate bonding strength, the process is studied systematically based on Abaquas software and experiments. In the numerical simulation, the film-substrate structure models with different acoustic impedance matching modes are established and the film thickness is changed. The stress distribution along the depth direction at different moments, the convex morphology of films, the maximum stress value and duration of different thickness films are all analyzed. The results show that, when the acoustic impedance of the film is weaker than that of the substrate, tensile stress at the interface between the film and substrate can be avoided by covering appropriate constraint layer on the film surface. In this case, the bonding strength is not weakened and the material surface properties are enhanced. When the acoustic impedance of the film is stronger than that of the substrate, conducting the laser shock or not depends on the processing purposes. When the stress is unavoidable, choices of material thickness should be cautious. Not only the strengthening effect of the material surface should be taken into account, but also the tensile stress at the interface between the film and substrate should be reduced..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503003 (2016)
Process Optimization of Laser Transmission Spot Welding Using Material PMMA for Automotive Industry
Liu Baoguang, Wang Xiao, Liu Wei, Guo Dehui, Zhong Xuejiao, and Liu Huixia
To quantify the need for the connection of a lightweight polymer in the automotive industry, the study on laser transmission spot welding of material PMMA for vehicle by NdYAG pulse laser is conducted. The mathematical model of the process parameters with the maximum tensile force and molten pool diameter is establisheTo quantify the need for the connection of a lightweight polymer in the automotive industry, the study on laser transmission spot welding of material PMMA for vehicle by NdYAG pulse laser is conducted. The mathematical model of the process parameters with the maximum tensile force and molten pool diameter is established by the response surface method, and it can be used to optimize and analyze the experimental design. The interaction effects of key parameters including voltage, frequency, stand-off distance, and exposure on the joint performance and the mean weld diameter are analyzed, and the optimization analysis is carried out based on two kinds of optimization criteria. The results show that the voltage and frequency can affect the joint performance by controlling the laser power, and the latter has a significant influence on laser transmission spot joining performance. When the laser power becomes higher, the energy density is more concentrated. In that case, if the laser action time increases, it is easy to initiate ablation or even penetration of samples. In the process of optimization, the relative error between the predicted value and the experimental one is less than 8%, so the predicted results of parameters optimization are consistent with the experimental ones. Above all, this study provides an effective direction to enhance the bond quality and minimize the bond cost..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503004 (2016)
Graded Coating Produced by Laser Melt Injection Under Steady Magnetic Field
Song Shiying, Wang Liang, Hu Yong, and Yao Jianhua
The WC/316L metal-matrix gradient coating was prepared by laser melt injection under a steady magnetic field. The influence of the steady magnetic field on the distribution of hard particles and the microstructure in the composite layer is discussed. The results show that the steady magnetic field can suppress the flowThe WC/316L metal-matrix gradient coating was prepared by laser melt injection under a steady magnetic field. The influence of the steady magnetic field on the distribution of hard particles and the microstructure in the composite layer is discussed. The results show that the steady magnetic field can suppress the flow of the molten pool and reduce the drag force on particles in the molten pool. With the increase of the magnetic flux density, the volume rate of WC particles in the upper part of the LMI layer increases. The phase type is preserved no matter whether the steady magnetic field is added or not. However, the content of W-phase significantly increases. The size of the eutectic structure becomes larger and the quantity does as well..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503005 (2016)
Melting and Solidifying Behavior in Single Layer Selective Laser of Pure Tungsten Powder
Zhou Xin, and Liu Wei
In order to realize the densification behavior of pure tungsten processed by selective laser melting, the single layer laser melting and solidifying of pure tungsten substrate and powder experiments are conducted to find the optimal processing parameters, and the balling phenomenon is observed. The balling process is eIn order to realize the densification behavior of pure tungsten processed by selective laser melting, the single layer laser melting and solidifying of pure tungsten substrate and powder experiments are conducted to find the optimal processing parameters, and the balling phenomenon is observed. The balling process is explained with spreading and solidifying of the molten droplets competition model. The pure tungsten droplets spread at a low speed for their high viscosity and surface tension, but they solidify simultaneously at a high speed driven by the existing steep temperature gradient. Due to their higher thermal conductivity and melting point, the molten droplets solidify entirely before spreading completely and keep their globular geometry instead of creating a flat layer. Increasing the laser absorptivity of powder and substrate helps reduce the balling tendency at the higher peak temperature. Compared with scan speed, adjusting the laser exposure time is more appropriate under pulse laser control. Favorable melt tracks can be fabricated with exposure time of 300 μs, for the balanced melt volume and temperature gradient..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503006 (2016)
Study on High Strength Al-Cu-Mg Alloy Fabricated by Selective Laser Melting
Zhang Hu, Nie Xiaojia, Zhu Haihong, Zeng Xiaoyan, and Yang Changhao
Al-Cu-Mg alloys are successfully fabricated by selective laser melting (SLM). The influence of the applied laser linear energy density on the densification behavior of SLM-processed samples is investigated. Microstructure and mechanical properties of the SLM-processed Al-Cu-Mg alloys are studied based on the nearly fulAl-Cu-Mg alloys are successfully fabricated by selective laser melting (SLM). The influence of the applied laser linear energy density on the densification behavior of SLM-processed samples is investigated. Microstructure and mechanical properties of the SLM-processed Al-Cu-Mg alloys are studied based on the nearly fully densified samples. Finally, the mechanical properties of the samples are improved by heat treatment. The results show that the nearly fully densified samples with the highest relative density of 99.8% can be obtained when the laser linear energy density is 2.4 kJ/m. The SLM-processed Al-Cu-Mg samples are constituted of ultrafine supersaturated cellular-dendrites. The tensile strength of 401 MPa, the yield strength of 252 MPa and the elongation of 6.5% are achieved for the SLM-processed Al-Cu-Mg samples in virtue of the effect of grain refinement and solid solution strengthening. After T4 heat treatment, under the effect of precipitation strengthening, the tensile strength increases to 532 MPa, the yield strength increases to 338 MPa and the elongation increases to 13%..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503007 (2016)
Pulse Fiber Laser Controlled Fracture Cutting of Ultrathin Strontium Titanate Ceramic Substrate
Jiang Wei, Xie Xiaozhu, Wei Xin, Hu Wei, Ren Qinglei, and Weng Qing
Strontium titanate ceramics with the feature of soft and brittle is difficult to process by mechanical processing method, because this method can easily cause crack and scratch on the surface. Master oscillator power amplifier (MOPA) pulsed fiber laser is conducted to controlled fracture cutting strontium titanate ceraStrontium titanate ceramics with the feature of soft and brittle is difficult to process by mechanical processing method, because this method can easily cause crack and scratch on the surface. Master oscillator power amplifier (MOPA) pulsed fiber laser is conducted to controlled fracture cutting strontium titanate ceramic substrate. The mechanism of laser controlled fracture cutting is revealed as follows. Firstly the grooves formed by laser ablation. The groove depth then increases with the increase of the scanning times. When the thermal stress reaches the fracture threshold value of the material, the crack extends along the stress groove until it is completely split. It is an adaptive splitting process without the subsequent breaking procedure. In addition, it is found that the surface flattening and smoothing phenomenon occurr in laser ablation of material. Strontium titanate ceramic substrate with the thickness of 0.3 mm can be shape cut by selecting appropriate laser processing parameters..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503008 (2016)
Temperature Distribution for Laser Etching of Metal Thin Films on Polyimide Substrate
Zhang Hongwei, Ren Ni, Xue Hongtao, Tang Fuling, Yan Xiaodong, Lu Wenjiang, and Liu Xiaoli
In order to study the pulse laser etching process of metal thin films on polyimide substrate, a two-dimensional transient physical model of Gaussian distribution pulse laser irradiation in composite material is established with the finite element analysis software COMSOL Multiphysics. The temperature distribution of meIn order to study the pulse laser etching process of metal thin films on polyimide substrate, a two-dimensional transient physical model of Gaussian distribution pulse laser irradiation in composite material is established with the finite element analysis software COMSOL Multiphysics. The temperature distribution of metal thin films is calculated under irradiation of pulse lasers with different powers by means of solving the thermal conduction equations. The influences of different laser parameters on etching process are discussed. Simulation results show that the ablation depth is mainly affected by the laser power density, and it decreases at first and then keeps constant with increase of metal film′s thickness. During the etching process, it is appropriate to choose laser parameters of higher power and shorter pulse width in order to well protect the substrate from damage. As copper film etching is much more difficult than aluminum film etching, higher laser power density should be selected for copper film etching. Results are instructive and helpful to understand the actual laser etching process..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 503009 (2016)
Laser Physics
Study of High Power Semiconductor Laser with Low Threshold Current
Liu Menghan, Cui Bifeng, He Xin, Kong Zhenzhen, Li Sha, and Huang Xinzhu
In order to solve the contradiction between large optical cavity (LOC) and low threshold current, a new semiconductor laser which has three quantum wells with higher barrier and asymmetric broad waveguide structure is designed. The laser can sustain low threshold current with large optical cavity. GaAs/AlGaAs three quaIn order to solve the contradiction between large optical cavity (LOC) and low threshold current, a new semiconductor laser which has three quantum wells with higher barrier and asymmetric broad waveguide structure is designed. The laser can sustain low threshold current with large optical cavity. GaAs/AlGaAs three quantum wells and 3.6 μm super large optical cavity waveguide are grown by metal organic chemical vapor deposition (MOCVD). The 980 nm semiconductor laser is fabricated. As a result, the threshold current of 4 mm LOC semiconductor laser is 1105.5 mA and the vertical divergence angle is 15.6°. An output power of 15.9 W is reached with injection current of 25 A. The results show that the designed structure is effective for light field expanding, which can realize large optical cavity and guarantee low threshold current..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 502001 (2016)
Laser Diode Pumped 4.1 kW All-Fiber Laser with Master Oscillator Power Amplification Configuration
Wang Xiaolin, Zhang Hanwei, Tao Rumao, Su Rongtao, Zhou Pu, and Xu Xiaojun
A laser diode (LD) pumped all-fiber laser with master oscillator power amplification configuration is demonstrated, of which output power is more than 4 kW. The stimulated Raman scattering (SRS) and transverse mode instability (TMI) charateristics of lasers are experimentally studied under different core-diameter gain A laser diode (LD) pumped all-fiber laser with master oscillator power amplification configuration is demonstrated, of which output power is more than 4 kW. The stimulated Raman scattering (SRS) and transverse mode instability (TMI) charateristics of lasers are experimentally studied under different core-diameter gain fibers and different pump wavelengths. In order to mitigate SRS, a large mode area Yb3+ doped fiber with core diameter of 30 μm is selected as gain media. In order to suppress TMI, LD with center wavelength of 915 nm is used as pump source, so the absorption coefficient of the gain fiber is lower at 915 nm, and the bending radius of the gain fiber is reduced to 10 cm to increase the loss of the higher modes. When the seed power is 100 W, the highest pump power is 5.3 kW, the laser power of 4.1 kW is achieved, and the beam quality M2 is 2.2. There are no SRS and TMI effects observed in the output laser..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 502002 (2016)
Study on a Non-Chain Discharge-Pumped Pulse Deuterium Fluoride Lasers
You Libing, Yin Guangyue, Wang Qinsheng, and Fang Xiaodong
The compact non-chain discharge-pumped pulse deuterium fluoride (DF) laser is studied, the discharge trigger circuit is introduced based on one-stage thyratron magnetic pulse with fast rise time. Discharging voltage of 39.5 kV and pulse rise time of 100 ns are achieved. With the condition of 190 J/L energy depositions,The compact non-chain discharge-pumped pulse deuterium fluoride (DF) laser is studied, the discharge trigger circuit is introduced based on one-stage thyratron magnetic pulse with fast rise time. Discharging voltage of 39.5 kV and pulse rise time of 100 ns are achieved. With the condition of 190 J/L energy depositions, a uniform glow discharge is formed using compact Chang-electrode combined with ultraviolet (UV) spark pre-ionization, and the distance between the cathode and anode is 30 mm. With flat-flat cavity laser resonators, mixture gas of SF6and D2is investigated. By optimizing the gas ratio to 10:3, the laser pulse energy is up to 877 mJ. The electro-optic conversion efficiency is about 1.9% and the pulse width is 200 ns with the beam dimensions of 30 mm×9 mm..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 502003 (2016)
Effects of Linewidth of Seed-Laser on Output Features of End-Pumped Alkali Vapor Amplifier
Jiang Zhigang, Wang You, Han Juhong, Cai He, Gao Ming, An Guofei, Xue Liangping, Zhang Wei, Wang Hongyuan, and Zhou Jie
In recent years, the diode pumped alkali laser (DPAL) has been rapidly developed as a new laser source. The master oscillator power-amplifier (MOPA) system is one of the most feasible engineering methods to achieve the high power scaling of DPAL. Comparing with traditional lasers, DPAL′s linewidths of both absorption aIn recent years, the diode pumped alkali laser (DPAL) has been rapidly developed as a new laser source. The master oscillator power-amplifier (MOPA) system is one of the most feasible engineering methods to achieve the high power scaling of DPAL. Comparing with traditional lasers, DPAL′s linewidths of both absorption and emission are extremely narrow. Therefore, the linewidth of a seed laser is one of the most important factors that effects the output characteristics of DPAL-MOPA. A theoretical microcosmic kinetic mode is established for an end-pumped DPAL-MOPA system. The linewidth of seed laser and the spectral distribution of emission cross-section are taken into account in the calculation process. The influences of linewidth of seed laser on the features, including the output power, output linewidth, extraction efficiency, gain factor, and pump absorption, are calculated and analyzed in detail. The research is helpful in construction of a power-scaled DPAL-MOPA system..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 502004 (2016)
Gain-Switched Semiconductor Pulsed Laser for Quantum Secure Communication
Zhou Qiang, Liu Jinlu, Gu Yuanhui, Fan Fan, Wang Yunxiang, and Xu Bingjie
In the last three decades, quantum information science and technology is one of the most exciting research fields. Among all the achievements, quantum secure communication technology is gradually started from experimental research to engineering application and expected to take the lead in achieving the commercial deveIn the last three decades, quantum information science and technology is one of the most exciting research fields. Among all the achievements, quantum secure communication technology is gradually started from experimental research to engineering application and expected to take the lead in achieving the commercial development. Towards the comprehensive popularization of the quantum secure communication system, a picosecond pulsed laser module has been designed and fabricated based on the gain-switching effect of the semiconductor laser and commercial electronic chips. The realized laser module has the following properties: operating wavelength at the low transmission loss window of fiber quantum channel, i.e., 1.5 μm; with a frequency fluctuation of less than 20 MHz; pulse time domain width of tens of picoseconds; no fixed phase correlation between any two pulses. Moreover, these properties are verified and discussed based on the requirement of weak coherent single photon source for quantum secure communication application..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 502005 (2016)
Materials and Thin Films
Development of Short-Medium Wave Energy Regulation Filter in Infrared Simulation System
Fu Xiuhua, Chen Zhihang, Zhang Jing, Xiong Shifu, and Fan Jiachen
As a new means of simulation, the infrared simulation is widely used in the military field for its high simulation credibility, good repeatability and low testing cost. To satisfy the requirements for infrared simulation system and to adjust the energy proportion of short-medium wave bands，we develop the filters. UsingAs a new means of simulation, the infrared simulation is widely used in the military field for its high simulation credibility, good repeatability and low testing cost. To satisfy the requirements for infrared simulation system and to adjust the energy proportion of short-medium wave bands，we develop the filters. Using Ge and SiO as coating materials because of the absorption characteristic of Ge in the visible and near-infrared wave band, superimposing two film stacks to broaden the reflection band, we design and optimize a two-band energy regulation and wide band cut filter by using variable metric method of TFCalc software. According to the characteristics of different materials, we make the corresponding filter by using electron beam evaporation and resistance deposition techniques. By using reverse engineering method, we analyze the effect of extinction coefficient on transmittance and solve the problem of low transmittance. Transmittance of the filter is less than 1% at 300 nm to 1900 nm and 5500 nm to 7500 nm, 90.6% at 2000 nm to 2500 nm, and 35.7% at 3700 nm to 4800 nm, which meets environmental testing requirements of the simulation system..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 507001 (2016)
Measurement and Metrology
Non-Contact In-Situ Dihedral Angle Measuring Approach Base on Rotary Ray-Scanning Mechanism
Wu Zhengang, Zeng Zhoumo, Li Xingqiang, Wu Xiangyu, and Fu Luhua
The measurement of dihedral angle is one of the most important measuring tasks in geometric measurement. Numerous and diverse angle measuring methods are proposed. However, few in-situ and automatic measuring methods are seriously and vigorously studied. To this end, a novel and simple angle measuring method is proposeThe measurement of dihedral angle is one of the most important measuring tasks in geometric measurement. Numerous and diverse angle measuring methods are proposed. However, few in-situ and automatic measuring methods are seriously and vigorously studied. To this end, a novel and simple angle measuring method is proposed, which is based on non-contact rotary ray-scanning mechanism. The rotary rays, emitted from a laser displacement sensor rotates around a fixed axis, constitutes the kernel part of the measuring probe. Which is driven to scan the surface of the workpiece. The distances from the target planes to the probe are obtained and subsequent data analysis is applied to calculate the dihedral angle. As an optional accessory, the measurement probe can be installed on the spindle of numerical control machine for in-situ measurements. The detailed mathematical model as well as the associated tolerance analysis are presented and validating experiments are offered. The method can do well in angle measuring within a nominal measuring range from 0° to 120°. The results are compared against the relative true value offered by three-coordinate measuring machine. It is shown that the maximal error of measuring result is 14″, and relative error of the proposed approach can be lower than 0.048% even in in-situ complex measuring environments..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 508001 (2016)
Optimal Pulsed Frequency and Scanning Speed of Laser Circumferential Detection System
Xu Xiaobin, and Zhang He
Aiming at the problem of matching between the scanning frequency and the speed of the motor of a single beam pulse laser detection system, the research on target detection of the single beam pulse laser detection system is carried out. In order to improve the detection probability of the laser detection system, a modelAiming at the problem of matching between the scanning frequency and the speed of the motor of a single beam pulse laser detection system, the research on target detection of the single beam pulse laser detection system is carried out. In order to improve the detection probability of the laser detection system, a model of the missile′s target intersection is established. The influence of laser pulsed frequency and motor scanning speed on the detection target probability of the circumferential detection system is analyzed by using Monte-Carlo method. According to the optimal laser pulsed frequency and motor speed, the principle prototype is designed and the simulating experiment is carried out. The experimental results show that in the case of 3 m detection range the detection system can detect the target effectively when the laser emission frequency is 20 kHz and motor speed is 30000 r/min, which provide the basis for the optimum laser emission frequency and the scanning frequency of the motor for the single pulse laser..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 508002 (2016)
Measurement of Residual Birefringence Combined Photo-Elastic Modulation with Electro-Optic Modulation
Li Kewu, Wang Liming, Wang Zhibin, Zhang Rui, Li Xiao, and Wang Shuang
In order to measure the residual birefringence and direction angle of fast axis simultaneously, with the advantage of high speed, high precision, high sensitivity, easy operation, good stability and low cost, the photo-elastic modulator (PEM) and electro-optic modulator(EOM) are combined, and the detector is used to deIn order to measure the residual birefringence and direction angle of fast axis simultaneously, with the advantage of high speed, high precision, high sensitivity, easy operation, good stability and low cost, the photo-elastic modulator (PEM) and electro-optic modulator(EOM) are combined, and the detector is used to detect signals and the locked-in amplifier is used to achieve the first harmonic term. Value and direction of birefringence are solved out by the direct current (DC) term and the first term in the computer, so the simultaneous measurement of value and direction of birefringence in a single photo-elastic modulation channel are realized. The principle of the new scheme is analyzed, and the experimental system is set up. The system is calibrated by the method of instrument offset, and the experimental analysis of a Berek polarization compensator is carried out. Experimental results show that the system calibration can effectively eliminate the measurement error maybe introduced by PEM and EOM themselves. The measuring accuracy and repeatability rate of residual birefringence for this scheme are better than 99.16% and 0.0082 rad, respectively. The measuring repeatability of direction angle of fast axis is 0.06°. This scheme has the advantages of stable operation, high repeatability rate, fast measurement speed, low cost, and conducive to industrial automation integration and so on..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 508003 (2016)
Phase Shift Extraction Algorithm by Special Points in Two-Step Generalized Phase-Shifting Interferometry
Zhou Zhisheng, Dong Yuming, Zhang Yizhou, Jiao Guohua, Lu Yuanfu, and Lü Jiancheng
A phase shift extraction algorithm based on the special points in two-step generalized phase-shifting interferometry is proposed. This algorithm searches the special points that meet specific requirements and calculates the phase shift via the latter′s relationship with these special points. It is divided into two modeA phase shift extraction algorithm based on the special points in two-step generalized phase-shifting interferometry is proposed. This algorithm searches the special points that meet specific requirements and calculates the phase shift via the latter′s relationship with these special points. It is divided into two modes according to whether the intensity distributions of the two interference beams are recorded or not. Theoretical analysis, computer simulation and experimental verification are carried out. Experimental results show that this algorithm reaches the same level of other algorithms in speed and accuracy. Moreover, when the interferogram′s fringe number is less than one, a better phase shift extraction accuracy can be obtained..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 508004 (2016)
Precision Analysis of Grating Replicated Mosaic Error Based on the Principle of Fraunhofer
Lu Yuxian, Qi Xiangdong, Yu Haili, Li Xiaotian, Zhang Shanwen, Jiang Shan, and Yin Lu
Replicated mosaic is an important way to make large size plane diffraction grating in astronomy. Considering cost control and grating development cycle, the mosaic system should be applicable to different parameters of grating and different test wavelengths. At the same time, the accuracy of the mosaic system must matcReplicated mosaic is an important way to make large size plane diffraction grating in astronomy. Considering cost control and grating development cycle, the mosaic system should be applicable to different parameters of grating and different test wavelengths. At the same time, the accuracy of the mosaic system must match the requirement. The mosaic error theory model is established based on the principle of Fraunhofer far field diffraction and the trend is analyzed and simulated when the wavelength of incident light, diffraction order, grating constant, and incident angle are changed. The variable range of above parameters is designed according to the actual mosaic demand. The mosaic error precision which can satisfy the usage requirement is computed when the grating parameters and detection conditions are changed. The simulation results will make a significant guidance for the replicated mosaic system design..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 508005 (2016)
Fast Pose Estimation Method for Unmanned Aerial Vehicle Based on Rectangular Geometry Feature
Hong Yang, Sun Xiuxia, Wang Dong, Liu Shuguang, and Wang Hanlin
In order to improve the vision navigation of unmanned aerial vehicle more real-timely and accurately, a pose estimation method step by step based on monocular vision is proposed using rectangular geometry feature and coplanar feature of points and lines. This proposed method shoots the rectangular target under any posiIn order to improve the vision navigation of unmanned aerial vehicle more real-timely and accurately, a pose estimation method step by step based on monocular vision is proposed using rectangular geometry feature and coplanar feature of points and lines. This proposed method shoots the rectangular target under any position, and two orthogonal vanishing points are achieved. The constraint equation of projection between infinite points and orthogonal vanishing points are established to calculate the rotation parameters. And also a constraint equation is established by using the coplanar feature of camera optical, rectangular target and its projection, which are used to solve the normal vector of rectangular target under camera coordinate system. Based on the invariance feature of linear transformation under Euclidean space, the four vertices of rectangular target under camera coordinate system can be linearly calculated and the solution of the translation estimation can be accomplished through the translation between camera and world coordinate system. Aiming at restraining the influence of noise to estimation, the indicated function based on the coplanar feature of points and lines is obtained, using the NM optimization algorithm to realize the nonlinear optimization of pose parameters. Experimental results show that the proposed method has the advantages of high precision, real-time and wide application. The robustness of estimation algorithm is improved by reducing the image noise through parameter optimization..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 508006 (2016)
Optical Communication
Amplitude Correction Method of Time-Wavelength Interleaved Photonic Analog-to-Digital Conversion
Ye Lei, Wu Guiling, Su Feiran, and Chen Jianping
In-channel amplitude noise and inter-channel amplitude mismatch are main factors limiting the performance of time-wavelength interleaved photonic analog-to-digital conversion (TWIPADC) system. An amplitude correction method based on adaptive noise cancellation principle for TWIPADC is proposed. In the scheme, the in-chIn-channel amplitude noise and inter-channel amplitude mismatch are main factors limiting the performance of time-wavelength interleaved photonic analog-to-digital conversion (TWIPADC) system. An amplitude correction method based on adaptive noise cancellation principle for TWIPADC is proposed. In the scheme, the in-channel amplitude noise introduced by unstability of the laser source and optical time division multiplexing (OTDM) module is eliminated in real time by using the adaptive interference cancellation principle, while the inter-channel amplitude mismatch introduced by the wavelength division multiplexing module is corrected by adopting a calibration procedure. The structure of TWIPADC system based on the proposed correction scheme is presented. The proposed amplitude correction principle and procedure are analyzed theoretically by building the corresponding mathematical model. The simulation results show that the amplitude noise of TWIPADC caused by optical source and OTDM module can be eliminated in real time effectively by the proposed adaptive cancellation scheme. The signal-to-noise-and-distortion ratio of a 32 GS/s TWIPADC system with 16-channel can be improved more than 30 dB by using the proposed amplitude correction method..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505001 (2016)
Detection Technique of Stress Waves Based on Fiber Bragg Grating
Sun Shihui, Yu Youlong, Li Hui, Qian Muyun, Zhao Zeng, Yin Shen, and Lai Xiaoming
The detecting method of stress wave generated by split Hopkinson pressure bar based on fiber Bragg grating (FBG) is proposed; the principle is outlined and the relationship between strain and center wavelength shift of FBG is discussed. The strain pulses generated by direct impact and impacting with the pulse shaper arThe detecting method of stress wave generated by split Hopkinson pressure bar based on fiber Bragg grating (FBG) is proposed; the principle is outlined and the relationship between strain and center wavelength shift of FBG is discussed. The strain pulses generated by direct impact and impacting with the pulse shaper are measured using the FBG and strain gauges which are axially symmetrically pasted to the same section of the cylindrical rod. It can be concluded that the time domain signal and the frequency spectrum of the results with FBG and strain gauges are consistent by contrast and analysis. The maximum strain reaches -1087.04 με with error of 2.26% for a given impacting velocity of 11.33 m/s. When FBG and the pulse shaper are adopted, the impacting veloctiy is 9.8 m/s, and the longitudinal wave speed is measured to be 5236.4 m/s with the error of 2.84%. The error range can meet the basic requirements of engineering tests..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505002 (2016)
Optimal Design and Experiments of Coated Dual-Peak Resonance Long-Period Fiber Grating Refractive Index Sensing
Jiang Xiuli, Gu Zhengtian, Ling Qiang, and Lan Jinlong
Highly sensitive refractive index sensing is realized by using dual-peak resonance long-period fiber grating (LPFG) with self-assembled coating. The way for improving the sensitivity of coated dual-peak resonance fiber gratings to the surrounding refractive index is given. The fiber cladding mode is located near the moHighly sensitive refractive index sensing is realized by using dual-peak resonance long-period fiber grating (LPFG) with self-assembled coating. The way for improving the sensitivity of coated dual-peak resonance fiber gratings to the surrounding refractive index is given. The fiber cladding mode is located near the mode transition zone by choosing optimal film thickness. The dual-peak structure of fiber coated is located near phase-matching turning point (PMTP) by adjusting the fiber radius. The method for determining optimal film thickness and fiber radius is given. Dual-peak gratings with different fiber radii coated with poly allylaminehydrochliride (PAH)/ poly acrylic acid (PAA) films are immersed in different concentrations of glucose solution to carry out refractive index sensing experiments. Results show that the sensitivity of coated dual-peak gratings operating near mode-transition regions and PMTP is 3985 nm/RIU in 1.333~1.372 index range, which is obviously higher than those of gratings not operating near mode-transition or PMTP, and also higher than that of non-dual-peak coated LPFGs reported..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505003 (2016)
A Novel Broadened Frequency Sweeping Optical Source with Wide Linewidth Based on Optical Recirculating Frequency Shifter
Li Lu, Du Jiangbing, Xu Changxin, Sun Lin, Li Jiaxiong, and He Zuyuan
Frequency sweeping optical source (FSOS) is widely used in optical communications, optical sensing and optical imaging. Sweeping span and sweeping speed of the FSOS is critical to its performance. A new method to broaden the sweeping span and accelerate the sweeping speed of the FSOS is proposed. Single sideband modulaFrequency sweeping optical source (FSOS) is widely used in optical communications, optical sensing and optical imaging. Sweeping span and sweeping speed of the FSOS is critical to its performance. A new method to broaden the sweeping span and accelerate the sweeping speed of the FSOS is proposed. Single sideband modulation is adopted in a recirculating frequency shifter to enhance the frequency sweeping electric-optic modulation and generate stable high-order optical comb. So a wider optical frequency sweeping span is obtained with narrow-band electrical sweeping signal given the identical linearity and narrow linewidth. An optical frequency sweeping span of 11.44 GHz is obtained by radio frequency sweeping span of 200 MHz, the frequency is broadened approximately by 57 times. Meanwhile, the frequency sweeping speed is improved by 57 times as each sweeping period remains not changed..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505004 (2016)
Distributed Feedback Fiber Laser Hydrophone Used in Towed Line Arrays
Tang Bo, Huang Junbin, Gu Hongcan, and Mao Xin
To further expand the working frequency band of the distributed feedback (DFB) fiber laser hydrophone, a 13-mm-diameter encapsulated structure with sensitivity enhanced through polyurethane end surface pulling is presented. The theoretical model of the relationship between acoustic pressure sensitivity and polyurethaneTo further expand the working frequency band of the distributed feedback (DFB) fiber laser hydrophone, a 13-mm-diameter encapsulated structure with sensitivity enhanced through polyurethane end surface pulling is presented. The theoretical model of the relationship between acoustic pressure sensitivity and polyurethane material parameters is established. After the relationship between the dynamics performance of hydrophone and polyurethane material parameters is simulated, the parameters of the two-component polyurethane are optimized. Prototypes of the hydrophone are fabricated and tested. The acoustic pressure sensitivity reaches (-137.60±2) dB in the frequency range of 10~20000 Hz, which shows that the working frequency band of the hydrophone is expanded through polyurethane end surface pulling and it can well meet the requirements for the engineering application of towed line arrays..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505005 (2016)
Reusing the Backward ASE in Tm-Ho Co-Doped Fiber Amplifiers Based on FBG
Long Hu, Yao Bo, and Mao Qinghe
Regarding to the problem that the backward amplified spontaneous emissions (ASE) in Tm-Ho co-doped fiber amplifier reduce the amplification efficiency beyond 2 μm band, the influence on gain property beyond 2 μm band by inserting a 1950 nm fiber Bragg grating (FBG) into the input terminal of the amplifiers with differeRegarding to the problem that the backward amplified spontaneous emissions (ASE) in Tm-Ho co-doped fiber amplifier reduce the amplification efficiency beyond 2 μm band, the influence on gain property beyond 2 μm band by inserting a 1950 nm fiber Bragg grating (FBG) into the input terminal of the amplifiers with different Tm/Ho doping ratios is studied theoretically. Simulation results of the 2040 nm signal gain over the fiber length with or without FBG are given under several different Tm/Ho doping ratios in order to analyze the variations of maximum gain and corresponding optimal fiber length due to the insertion of FBG, as well as the dependence of the variations on Tm/Ho doping ratio. The influence of FBG is explained through simulating the backward ASE spectrum at z=0, and the propagation of pump, signal, ASE and reflected light from FBG along the fiber. Discussions on the simulation results further point out the applicable conditions of short-band FBG for improving long-band gain of amplifier. In addition, the influences on gain spectrum and noise characteristics by FBG are also investigated..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505006 (2016)
Frequency-Selectable and Multi-Channel Wavelength Division Multiplexing Radio-over-Fiber System
Han Yishi, Luo Zhixiao, Qin Xinyu, and Zheng Zhenyu
A frequency-selectable and multi-channel wavelength division multiplexing radio-over-fiber system is studied. The system is able to transmit at most 4-channel frequency-selectable downstream millimeter wave (MMW) signals and 2-channel to 4-channel upstream signals. Simulation results show that the proposed system can gA frequency-selectable and multi-channel wavelength division multiplexing radio-over-fiber system is studied. The system is able to transmit at most 4-channel frequency-selectable downstream millimeter wave (MMW) signals and 2-channel to 4-channel upstream signals. Simulation results show that the proposed system can generate MMW signals with different frequency multiplication factors by 7×8 digital optic switch, such as 2, 4, 6, 8, 10 and 12. After 50 km standard single mode fiber transmission, the power penalty of the downstream MMW signals is from 1.21 dB to 1.71 dB under the bit error rate of 10-9, while the power penalty for upstream signals is from 1.10 dB to 1.24 dB. The proposed system is successfully verified with characteristics of equalization and dispersion mitigation..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505007 (2016)
New Pulse-Position Modulation Technology in Deep-Space Optical Communications
Wang Yan, Zhang Huaxun, Zhang Meng, and Sun Haixin
In deep-space optical communications, the pulse-position modulation (PPM) is a common way of modulation. But in the conventional multiple pulse-position modulation (MPPM), the number of transmitted light pulses per signal block is fixed. With the development of deep space exploration technology, the requirement of the In deep-space optical communications, the pulse-position modulation (PPM) is a common way of modulation. But in the conventional multiple pulse-position modulation (MPPM), the number of transmitted light pulses per signal block is fixed. With the development of deep space exploration technology, the requirement of the modulation mode must be increasing. It is necessary to improve the MPPM to meet the requirements of deep space optical communication. So we propose a new modulation scheme (n pulse XPPM) to improve both the symbol-error rate (SER) and the bandwidth-utilization efficiency. Based on the transmission characteristics of XPPM, the modulation rate, required power and bandwidth are derived and compared with L-level pulse-position modulation (LPPM) and MPPM. At the same average power, the XPPM scheme achieves much lower levels of SER than the ordinary MPPM scheme. And n pulse XPPM has more advantages than the two other PPM ways in terms of the transmission rate and the required bandwidth. Results of the simulated experiment reveal that the transmission rate and the bandwidth-utilization efficiency of system can reach 2.746 Mbit/s and 85% or more, respectively, when the communication distance of deep space optical communication system from the earth to the mars is 4×1011 m using XPPM..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505008 (2016)
Characteristics of Light Source Based on Dual Polarization Fiber Optic Gyroscope
Liao Huiqi, Luo Rongya, Deng Sheng, Peng Chao, Zhao Jianye, Gao Fanmin, and Li Zhengbin
Polarization nonreciprocal phase error is one of major errors in fiber optic gyroscope (FOG). In dual polarization FOG, the polarization nonreciprocal phase error in two orthogonal polarization modes possesses opposite signs, which can be compensated optically. The influences of light source on performance of dual polaPolarization nonreciprocal phase error is one of major errors in fiber optic gyroscope (FOG). In dual polarization FOG, the polarization nonreciprocal phase error in two orthogonal polarization modes possesses opposite signs, which can be compensated optically. The influences of light source on performance of dual polarization FOG are discussed based on the dual polarization FOG theory and model, which shows that the bias stability of dual polarization FOG is improved by short coherence length and low degree of polarization (DOP). Experiment results show that super luminescent diode (SLD) or super-fluorescent sources (SFS) can be adopted to compensate polarization nonreciprocal error effectively under conditions of short coherence length and low DOP in dual polarization FOG..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 505009 (2016)
Rapid Communications
[in Chinese]
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Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 519001 (2016)
Optical Design and Fabrication
Research on Temperature Distribution of Deep Ultraviolet Lithographic Projection Objective
Yao Changcheng, and Gong Yan
As for the deep ultraviolet (UV) lithographic projection objective, the laser energy absorbed by the lens material causes temperature rise, which induces thermal aberration. Under the off-axis illumination mode, the temperature distribution is non-symmetric, and thus the research on the temperature distribution is signAs for the deep ultraviolet (UV) lithographic projection objective, the laser energy absorbed by the lens material causes temperature rise, which induces thermal aberration. Under the off-axis illumination mode, the temperature distribution is non-symmetric, and thus the research on the temperature distribution is significant for thermal aberration simulation, prediction and compensation.A temperature distribution function model is proposed to describe the three-dimensional temperature distribution of the lens in four illumination modes. Simultaneously, the relationship between temperature and exposure time is studied, and the temperature at the thermal steady state and the consumed time to get steady is calculated. The results show that the temperature distribution models perform well for describing the spatial temperature distribution of projection lens under several commonly used illumination modes with an average fitting error of about 10-3 ℃. The error of thermal steady temperature predicted via the relationship between temperature and time is about 10-4 ℃, and the time error is less than 3 min. The thermal aberration results calculated by the proposed model agree with the simulation results by SigFit, while the time cost shows a decrease of three orders of magnitude..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 516001 (2016)
Remote Sensing and Sensors
Long-Distance Laser Ranging Lidar Based on Photon Counting Technology
Luo Yuan, He Yan, Geng Liming, Wang Mingjian, Lei Linjun, Wu Yaofang, Hu Shanjiang, Hou Xia, and Chen Weibiao
For the application of laser detection over a long distance of 100 km, to achieve the long-distance detection, the system mostly uses low repetition frequency, high pulse energy laser and large diameter telescope, which leads the shortcomings of large volume, heavy weight and high power consumption. The lidar based on For the application of laser detection over a long distance of 100 km, to achieve the long-distance detection, the system mostly uses low repetition frequency, high pulse energy laser and large diameter telescope, which leads the shortcomings of large volume, heavy weight and high power consumption. The lidar based on photon counting technology has the characteristic of high sensitivity. It greatly reduces the laser energy and receiving telescope aperture of the system. The volume, weight and power consumption of the system are reduced. A kind of laser ranging lidar applied in high-altitude remote detection of small target is designed, which adopts Geiger-mode avalanche photo diode achieving photon counting, and realizes the miniaturization of the system. The system design principle, component, and the experiment result are introduced in detail. The results show that when the round-trip atmospheric transmittance is 0.25, the maximum detection range can reach 100 km for the small target with 6 m2 effective reflection area and 0.1 reflectivity, and the range resolution is 6 m..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 514001 (2016)
Buildings Detection and Contour Extraction by the Fusion of Aerial Images and LIDAR Point Cloud
Cheng Xiaojun, Cheng Xiaolong, Hu Minjie, Guo Wang, and Zhang Lishuo
The method of extracting building boundaries based on the fusion of airborne radar (LIDAR) point cloud and aerial images is proposed by analyzing the feature of airborne LIDAR point cloud data and aerial images data. The contour line of buildings are extracted from both the point cloud and the aerial images. The contouThe method of extracting building boundaries based on the fusion of airborne radar (LIDAR) point cloud and aerial images is proposed by analyzing the feature of airborne LIDAR point cloud data and aerial images data. The contour line of buildings are extracted from both the point cloud and the aerial images. The contour line is fitted to lines of the building boundaries. The building vertexes are derived from two adjacent and vertical boundaries. The registration fusion of airborne point cloud and aerial images is achieved according to the correspondence vertexes of building. The point clouds get the spectral information of aerial images, which is used as a feature vector of clustering analysis to extract plants, trees and other objects. The height information is used to extract building from the buildings and roads which have similar spectral information, and the accurate boundaries of buildings are extracted and the detection of the boundaries of building is achieved. Experimental results indicate that the accuracy of point cloud classification can reach 97.96%, and the precision of the extraction of building boundaries can be up to 0.21 m, which ensures an effective way of detecting building boundaries..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 514002 (2016)
Reflective Fluorescence Temperature Sensor Based on Dual-Granularity CdSe/ZnS Doped Quantum Dots Thin Films
Geng Yan, and Wang Helin
A reflective fluorescence temperature sensor based on the dual-granularity CdSe/ZnS doped quantum dots (QDs) thin films is designed. The CdSe/ZnS doped quantum dots thin films with the emitting wavelengths of 540 nm and 610 nm are applied to the system as a key device. The optical characteristics of photoluminescence (A reflective fluorescence temperature sensor based on the dual-granularity CdSe/ZnS doped quantum dots (QDs) thin films is designed. The CdSe/ZnS doped quantum dots thin films with the emitting wavelengths of 540 nm and 610 nm are applied to the system as a key device. The optical characteristics of photoluminescence (PL) spectra with the change of temperature between 30 ℃ to 100 ℃ are studied, such as the peak wavelengths of PL spectra, the energy bandgaps of the QDs, the peak intensity of PL spectra and the self-referenced intensity of PL spectra. Results show that, the peak intensity of PL spectra decreases gradually with the increase of temperature; the peak wavelengths of PL spectra, the energy bandgaps of the QDs and the self-referenced intensity of PL spectra vary linearly with the temperature; the peak intensity of PL spectra can be denoted by exponential function of the temperature; the stability of the self-referenced intensity of PL spectra shows good during heating and cooling; the red shift of the the peak wavelengths happens with the increase of the temperature, and the average resolution of the designed reflective fluorescence QDs temperature sensor can reach 0.055 nm/℃..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 514003 (2016)
Spectroscopy
Study on Three-Dimensional First-Order Derivative Fluorescence Spectra of Oil Mixture Based on U-PLS/RQL
Wang Yutian, Zhao Xu, Xu Jing, Yuan Yuanyuan, Zhang Yaji, and Niu Kaizeng
The mixture of gasoline, kerosene and diesel is taken as the research object, in which diesel is considered as interferent, to analyze the content of gasoline and kerosene in the mixture. A new method is proposed to determinate the ingredient in the oil mixture and corresponding content of the component by analyzing thThe mixture of gasoline, kerosene and diesel is taken as the research object, in which diesel is considered as interferent, to analyze the content of gasoline and kerosene in the mixture. A new method is proposed to determinate the ingredient in the oil mixture and corresponding content of the component by analyzing the three-dimensional fluorescence spectral data. The method combines unfolded partial least-squares (U-PLS) with residual quadrilinearization (RQL) to process the first-order derivative three-dimensional fluorescence spectra of the oil mixture, which are extended to five-dimensional derivative spectra by using the Savitzky-Golay polynomial fitting differential to calculate the partial derivatives of the x axis and y axis of the spectral data. The calibration model of the fourth-order data is established by U-PLS/RQL to analyze the samples to be predicted, and the spectral data are decomposed and identified reasonably. The relative error of prediction is reduced to less than 5.0%, and the prediction accuracy is improved compared with that of the third-order multivariate calibration method..
Chinese Journal of Lasers
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 5, 515001 (2016)
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