Journals >Laser & Optoelectronics Progress
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2014
Volume: 51 Issue 8
29 Article(s)
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Detectors
Analysis and Solution of Two-Phase FT-CCD Charge Overflow Phenomenon
Liu Yi, Zhou Qing, and Yin Dayi
Charge overflow phenomenon will arise when CCD is receiving strong signals. With CCD without overflow drains, the parameters of the imaging system have to be set properly to avoid charge overflow. Based on the charge overflow phenomenon when using HAMAMATSU Frame-Transfer CCD to image not so strong targets, according tCharge overflow phenomenon will arise when CCD is receiving strong signals. With CCD without overflow drains, the parameters of the imaging system have to be set properly to avoid charge overflow. Based on the charge overflow phenomenon when using HAMAMATSU Frame-Transfer CCD to image not so strong targets, according to the paper, it is caused by the long-time charge accumulation of the image section during line readout process. To remove the overflow signal effectively, multiple frame transfers are carried out before integration time. Integrating sphere tests are also performed to testify the reason and the solution..
Laser & Optoelectronics Progress
- Publication Date: Jul. 10, 2014
- Vol. 51, Issue 8, 80401 (2014)
Radiation Response Matrix of Array Charge Couple Device
Ye Zhao, Wang Chao, Dong Xiaojing, and Zhu Jun
As a sensor to convert image from optical to electrical signal, charge coupled device (CCD) has been paid much attention to its image quality which is directly related to the radiation response characteristic parameters. Since array CCD is gaining more and more popularity, a concept of“radiation response matrix” and anAs a sensor to convert image from optical to electrical signal, charge coupled device (CCD) has been paid much attention to its image quality which is directly related to the radiation response characteristic parameters. Since array CCD is gaining more and more popularity, a concept of“radiation response matrix” and an evaluation method are put forward, and used to describe radiation response of each pixel of CCD. By analyzing of this matrix, and clearly defining physical concept of each element, parameters such as absolute radiation response, non-linearity, dark noise, signal-to-noise of each pixel and non-uniformity of CCD are in one-to-one correspondence with mathematical relation of the matrix. Response characteristic coefficient of each pixel is obtained using the model of radiation response matrix analysis by a test on area CCD DALSAFTF6080M. One application of this matrix is demonstrated. Experimental results show that non-uniformity of this CCD is 3.1% , its response is linear, and its dark noise is 3.84. This method is feasible and practical, and it satisfies the requirement of the objective evaluation of array CCD..
Laser & Optoelectronics Progress
- Publication Date: Jul. 04, 2014
- Vol. 51, Issue 8, 80402 (2014)
Fiber Optics and Optical Communications
Study on Optical Bistability Using Fiber Mach-Zehnder Interferometer
Zhu Xiaoliang, and Zhang Xiaodong
A new hybrid optical bistability device which comprises a fiber Mach-Zehnder interferometer and two fiber couplers is proposed. In the device, the fiber Mach-Zehnder interferometer is used as light intensity modulator and the fiber couplers are used to construct on optoelectronic feedback loop. The theory of bistabilitA new hybrid optical bistability device which comprises a fiber Mach-Zehnder interferometer and two fiber couplers is proposed. In the device, the fiber Mach-Zehnder interferometer is used as light intensity modulator and the fiber couplers are used to construct on optoelectronic feedback loop. The theory of bistability has been analyzed and illustrated. At last, the optical bistability is fulfilled by changing the input optical power in the experiment. The device can be used as a fiber laser power stabilizer when it works at the stable status and as an optical switch or optical router when it works at the switching status..
Laser & Optoelectronics Progress
- Publication Date: Jul. 21, 2014
- Vol. 51, Issue 8, 80601 (2014)
Acoustic Signal Detection Technology Based on the Frequency-Modulated Continuous Wave Interferometric Fiber Acoustic Sensor
Zhao Feng, Guo Ge, Li Dong, Wang Lixin, Liu Xiwen, and Yang Song
For the phase induced signal fading, the principles of interferometric fiber acoustic sensors based on sinusoidal-wave frequency-modulated continuous wave (FMCW) and sawtooth-wave FMCW are introduced, and two corresponding digital demodulation methods are described. Based on the principles an experimental system is buiFor the phase induced signal fading, the principles of interferometric fiber acoustic sensors based on sinusoidal-wave frequency-modulated continuous wave (FMCW) and sawtooth-wave FMCW are introduced, and two corresponding digital demodulation methods are described. Based on the principles an experimental system is built including a fiber acoustic sensor with 7.5 m arm-difference and an FMCW laser source. Digital signal demodulations under 10 kHz sinusoidal-wave FMCW and 10 kHz sawtooth-wave FMCW are finished and comparative analysis between the demodulation results is performed. The experimental results show that both of the demodulation methods can detect the analog acoustic signal added to the acousthic sensor and eliminate the phase induced signal fading phenomenon of fiber interferometer. But the one based on sawtooth-wave FMCW possesses high and stable sensitivity with a simpler algorithm. Furthermore in this method a frequency division multiplexing system can be easily got by changing the arm difference of the fiber sensor..
Laser & Optoelectronics Progress
- Publication Date: Jul. 23, 2014
- Vol. 51, Issue 8, 80602 (2014)
Study on the Attenuation of Different Infrareds Transmission in Fog
Cong Rijin, Wang Jingyuan, Wang Rong, Xu Zhiyong, Cheng Muchun, and Zhang Qiwei
An infrared atmospheric transmission model is established based on photon tracing，and the theoretical equation for pass loss has also been derived. Through comparing pass losses calculated by Lambert-Beer law and Monte- Carlo method we know that the scattering energy received by the receiver cannot be ignored. The tranAn infrared atmospheric transmission model is established based on photon tracing，and the theoretical equation for pass loss has also been derived. Through comparing pass losses calculated by Lambert-Beer law and Monte- Carlo method we know that the scattering energy received by the receiver cannot be ignored. The transmission characteristics of near infrared, mid- infrared and far infrared under different visibilities and communication ranges are achieved. The results reveal that the pass loss of 10.6 μm is the minimum under the radiation fog. While under the advection fog, 0.85 μm has the minimum pass loss when the visibility is below 200 m, and 10.6 μm has the minimum pass loss when the visibility is over 200 m..
Laser & Optoelectronics Progress
- Publication Date: Jun. 28, 2014
- Vol. 51, Issue 8, 80603 (2014)
Research on Sensing Characteristic of a Micro-Region Etched Long-Period Fiber Grating Michelson Interferometer
He Rushuang, Zhang Bin, Tao Weidong, Yan Feibiao, Duan Tianchen, and Dong Jianfeng
Based on a single long period fiber grating (LPFG) with optical fiber pigtail coated with highreflective film, a LPFG Michelson interferometer with partly etched fiber cladding LPFG is designed. It improves the LPFG sensitivity. By applying interference principle, the change of interference peaks along with environmentBased on a single long period fiber grating (LPFG) with optical fiber pigtail coated with highreflective film, a LPFG Michelson interferometer with partly etched fiber cladding LPFG is designed. It improves the LPFG sensitivity. By applying interference principle, the change of interference peaks along with environment refractive index is obtained. The refractive index sensitivity of no etched LPFG Michelson interferometer is compared with that of the etched LPFG Michelson interferometer, results show that the change of the refractive index sensitivity is significantly improved. The peak wavelength of interferometer shifts from 0.9 nm to 3.4 nm when liquid refractive index is 1.333 and 1.352..
Laser & Optoelectronics Progress
- Publication Date: Jul. 02, 2014
- Vol. 51, Issue 8, 80604 (2014)
Performance Analysis of Improved T-PPM Technology on Atmospheric Turbulence
Guo Qiang
T-PPM code combines trellis coded modulation (TCM) and pulse amplitude modulation (PPM). It has both advantages in error correction and power efficiency of emission signal, and it has broad application prospects in space optical communications. The traditional T-PPM modulation and coding has shortage in mapping steps wT-PPM code combines trellis coded modulation (TCM) and pulse amplitude modulation (PPM). It has both advantages in error correction and power efficiency of emission signal, and it has broad application prospects in space optical communications. The traditional T-PPM modulation and coding has shortage in mapping steps which limits the reliability of the system. In order to improve the bit error performance of atmospheric turbulence optical communication system, an improved T-PPM technology suitable for singlecarrier weak turbulence is proposed. It uses Gray code mapping instead of the traditional“subset”mapping of TCM to reduce the possibility of error decision in receiving. Simulation results show that Gray code mapping can obviously improve bit error performance; at the bit error rate (BER) level of 10-3, compared with“subset” mapping, the Gray code mapping increases coding gain by about 0.2 dB; at pulse expansion level (1 ps and 2 ps), the Gray code mapping scheme can reduce the BER to about 1/2 and 4/5 of that of conventional “subset” mapping scheme, thus proving the priority of Gray code mapping..
Laser & Optoelectronics Progress
- Publication Date: Jul. 23, 2014
- Vol. 51, Issue 8, 80605 (2014)
Ultra Broadband Optical Fibers and Ultra Broad Telecom Systems
Wang Yeheng
The article concerning state- of the art of photonic crystal fibers is compared with that concerning ultra broadband single- mode triple- clad fibers (UBSM- TCF) optimized by target- oriented design method (TODM). A physical model and TODM are introduced based on macroscopic Maxwell equations. Acceptable tolerances of The article concerning state- of the art of photonic crystal fibers is compared with that concerning ultra broadband single- mode triple- clad fibers (UBSM- TCF) optimized by target- oriented design method (TODM). A physical model and TODM are introduced based on macroscopic Maxwell equations. Acceptable tolerances of three control parameters for mass production of UBSM- TCF optimized by TODM are estimated. Ultra broadband optical fibers and ultra broadband telecommunication systems are studied to serve the national strategy of broadband china. Three targets of national optical fiber industry are discussed..
Laser & Optoelectronics Progress
- Publication Date: Jul. 04, 2014
- Vol. 51, Issue 8, 80606 (2014)
Study on High Power Inter-Channel Crosstalk Attack in Optical Networks
Zhang Yinfa, Ren Shuai, Liao Xiaomin, and Li Juan
The mechanism of high power inter-channel crosstalk attack is analyzed theoretically. The conclusion that power of attack signal and fiber nonlinear refractive index are the main factors causing destructive effect on quality of legitimate signals due to high power inter-channel crosstalk attack is obtained. The effectsThe mechanism of high power inter-channel crosstalk attack is analyzed theoretically. The conclusion that power of attack signal and fiber nonlinear refractive index are the main factors causing destructive effect on quality of legitimate signals due to high power inter-channel crosstalk attack is obtained. The effects of high power inter-channel crosstalk attack on quality of legitimate signals and its attack propagation capability are investigated by building a simulation system in VPI software and using the bit error rate (BER) as evaluation index. The results show that high power inter-channel crosstalk leads to quality deterioration of legitimate signals propagated in the same fiber as the attack signal. The higher the power of attack signal is, the closer the channel spacing away from the attack signal is and the greater the fiber nonlinear refractive index is, the more the serious legitimate signals are affected by attack. The high power inter-channel crosstalk has an ability of attack propagation, and attack effect of the attack signal can be propagated to the fourth optical cross-connects (OXC4) when the power of attack signal is 27 dB higher than that of the legitimate signals..
Laser & Optoelectronics Progress
- Publication Date: Jun. 12, 2014
- Vol. 51, Issue 8, 80607 (2014)
Fourier Optics and Signal Processing
Vortex Phase Retrieval for Detecting System Aberration Based on Liquid Crystal Spatial Light Modulator
Wu Huaqin, Zheng Mingjie, Li Zhifang, Chen Daqiang, and Li Hui
We present a vortex phase retrieval method based on liquid crystal spatial light modulator. It's different from traditional phase retrieval method. In this method, a liquid crystal spatial light modulator is used to show the optical vortex phase, and a CMOS camera captures the donut image. A modified GS algorithm iWe present a vortex phase retrieval method based on liquid crystal spatial light modulator. It's different from traditional phase retrieval method. In this method, a liquid crystal spatial light modulator is used to show the optical vortex phase, and a CMOS camera captures the donut image. A modified GS algorithm iteratively calculates the target phase with a random phase input and amplitude before LCD surface. The procedure recovers the vortex phase after several iterative calculation and it is confirmed that the method can be workable. Finally, we calculate the system optical aberration and quantitatively analyze the aberration by using Zernike decomposition..
Laser & Optoelectronics Progress
- Publication Date: Jul. 17, 2014
- Vol. 51, Issue 8, 80701 (2014)
Holography
Study on a Method for Segmentation of Atomization Field Holography in a Combustion Chamber
Han Changcai, Cao Na, Lei Lan, Cao Liang, Xu Qing, and Ouyang Xiaoping
By counting the detected particles in atomization field holographic image at different threshold levels, a threshold estimation algorithm, which is based on detected particle number varying with the threshold level, is modeled and the rules for optimizing threshold are generalized. For particle field holography with paBy counting the detected particles in atomization field holographic image at different threshold levels, a threshold estimation algorithm, which is based on detected particle number varying with the threshold level, is modeled and the rules for optimizing threshold are generalized. For particle field holography with particle size less than 20 μm , the position corresponding to the smallest value in the difference curve of detected particle number varying with threshold levels, is defined as the best threshold. The results from a practical experiment show that this method can work well under such conditions..
Laser & Optoelectronics Progress
- Publication Date: Jun. 27, 2014
- Vol. 51, Issue 8, 80901 (2014)
Design and Application of a High-Precision Non-Contact Conoscopic Holographic Measure System
Wen Ya′nan, Wang Tian, Yu Jia, Yang Yu, Wang Jincheng, Wang Zhihong, and Tian Weijian
Based on the principle of conoscopic holography, a high-precision non-contact measure system is designed for the measurement of typical industrial parts. Using this system, height information of coin surface is acquired. After recording of the conoscopic holograms of the coin, the interference fringes are processed by Based on the principle of conoscopic holography, a high-precision non-contact measure system is designed for the measurement of typical industrial parts. Using this system, height information of coin surface is acquired. After recording of the conoscopic holograms of the coin, the interference fringes are processed by centerline refinement, through which we can calculate the variation in the fringe width, and thus obtain the height information of the coin surface. The results show that when the focal distance of objective is 50 mm the accurate measurement range of the system is 5 mm, with a maximum error of 0.28%, verifying the feasibility and accuracy of the conoscopic holographic measure system..
Laser & Optoelectronics Progress
- Publication Date: Jul. 16, 2014
- Vol. 51, Issue 8, 80902 (2014)
Imaging Systems
Character Analysis on Continuous-Wave Terahertz Reflection-Mode Confocal Scanning Microscopic Imaging
Yang Yongfa, Li Qi, and Hu Jiaqi
Due to high resolution and the ability of reconstructing 3D image of the sample, the terahertz reflection-mode confocal scanning microscopic imaging has great application value. A terahertz reflectionmode confocal scanning microscopic imaging experimental light path is designed. Under the condition of system parametersDue to high resolution and the ability of reconstructing 3D image of the sample, the terahertz reflection-mode confocal scanning microscopic imaging has great application value. A terahertz reflectionmode confocal scanning microscopic imaging experimental light path is designed. Under the condition of system parameters, the axial response characteristics of the system is calculated and analyzed in the case of two kinds of different wavelengths (118.83 μm and 184.31 μm ). The results of emulation show that the designed experimental device with wavelength of 118.83 μm gains a transverse resolution of 0.23 mm and an axial resolution of about 4.27 mm. When the wavelength is 184.31 μm , the transverse resolution is 0.36 mm and the axial resolution is about 6.63 mm. In comparison with the transverse offset, the axial offset of the detector brings a greater effect..
Laser & Optoelectronics Progress
- Publication Date: Jul. 21, 2014
- Vol. 51, Issue 8, 81101 (2014)
Instrumentation, Measurement and Metrology
Study on Application of Fiber Dot Light Source and Evaluation of the Spherical Wave Produced by Fiber Dot Light Source
Mo Weidong, Fan Qi, Fu Zhentang, Feng Mingde, and Wang Yunfei
The optic interference experiment and testing inspection systems with fiber dot light sources need the fewest optical components, have the best environmental and mechanical stability，and can get highprecision benchmark spherical wave so that there are the minimum errors for the system. For this purpose, the factors thaThe optic interference experiment and testing inspection systems with fiber dot light sources need the fewest optical components, have the best environmental and mechanical stability，and can get highprecision benchmark spherical wave so that there are the minimum errors for the system. For this purpose, the factors that influence the quality of optical fiber dot light source are analyzed. Applying the basic theory of light transmission in fiber, the method to improve the performance of fiber dot light source has been found. By the way of digital holography, the interference patterns of spherical wave produced by two fiber dot light sources are analyzed and computed, and the precision of the spherical wave is evaluated. The results show that the spherical wave produced by fiber dot light sources can meet the requirement of general interference inspection system on precision of benchmark spherical wave..
Laser & Optoelectronics Progress
- Publication Date: Jul. 23, 2014
- Vol. 51, Issue 8, 81201 (2014)
Design and Performance Analysis of Aircraft Wake Vortex Coherent Laser Detection System
Xu Shilong, Hu Yihua, and Guo Liren
In order to ensure flight safety and to improve the capability of the airport runway as far as possible, an aircraft wake vortex coherent laser detection system is designed. Begin with the requirements of wake vortex laser detection, the structure of the system is proposed. The parameters of the laser source and the opIn order to ensure flight safety and to improve the capability of the airport runway as far as possible, an aircraft wake vortex coherent laser detection system is designed. Begin with the requirements of wake vortex laser detection, the structure of the system is proposed. The parameters of the laser source and the optical path of the double balance detection are designed at the same time. The performance simulation proves that this detection system can meet the detection requirements. When the output energy is higher than 25 mJ, the detection signal-to-noise-ratio (SNR) can be up to 3 dB at the distance of 7 km and the detection accuracy is better than 0.2 m/s within 2 km..
Laser & Optoelectronics Progress
- Publication Date: Jul. 23, 2014
- Vol. 51, Issue 8, 81202 (2014)
A Multi-Degree-of-Freedom Geometric Errors Measurement Method
Zhai Yusheng, Zhang Zhifeng, Su Yuling, Wang Xinjie, and Feng Qibo
A novel method for simultaneous measurement of multi-degree-of-freedom geometric errors is presented based on laser collimation technique. A single-mode fiber-coupled laser module is used as source and a corner-cube prism and a splitting rectangular prism are adopted in the moving target to sense the straightness errorA novel method for simultaneous measurement of multi-degree-of-freedom geometric errors is presented based on laser collimation technique. A single-mode fiber-coupled laser module is used as source and a corner-cube prism and a splitting rectangular prism are adopted in the moving target to sense the straightness errors and angular errors, respectively. In this way, the horizontal and vertical straightness errors as well as pitch, yaw and roll angle errors can be measured simultaneously. Meanwhile, the moving part is wireless. The theoretical analysis and experimental results show that the method is feasible. With the supposed system parameters, the resolution the straightness, pitch, yaw and roll angle error, can reach to 0.1 μm , 0.1″ and 0.3″, respectively..
Laser & Optoelectronics Progress
- Publication Date: Jul. 28, 2014
- Vol. 51, Issue 8, 81203 (2014)
Large Aperture Reflection Mirror Figure Analysis with Singular Value
An Qichang, Zhang Jingxu, and Yang Fei
We introduce a singular value method to evaluate the mid- and high- frequency error in the large aperture reflecting mirror figure due to gravity print through and noise from processing and measurement. Firstly, we study the singular value method applied to mirror figure evaluaton. Then, the feasibility that the singulWe introduce a singular value method to evaluate the mid- and high- frequency error in the large aperture reflecting mirror figure due to gravity print through and noise from processing and measurement. Firstly, we study the singular value method applied to mirror figure evaluaton. Then, the feasibility that the singular value method can be applied to the reflecting mirror figure is verified by numerical simulation. Finally, the proposed method is applied to autual evaluation of the reflecting mirror figure, and the results with highfrequency error in the system eliminated are obtained. The proposed method may help evaluate the large aperture reflecting mirror figure with lower signal to noise ratio..
Laser & Optoelectronics Progress
- Publication Date: Jun. 28, 2014
- Vol. 51, Issue 8, 81204 (2014)
Lasers and Laser Optics
Study on a High Power QCW 355 nm Laser Diode Pumped Solid State Laser
Tian Ming, Wang Fei, Li Yuyao, Jiao Zhengchao, Luo Kuan, Che Ying, and Wang Xiaohua
A laser diode( LD) side pumped acousto- optic Q- switched Nd:YAG solid state 355 nm ultraviolet laser is reported by using intra cavity double frequency and sum frequency mixing. The Nd:YAG crystal is sidepumped by a LD, the intra cavity green radiation is generated using a type I non- critical phase matched littium trA laser diode( LD) side pumped acousto- optic Q- switched Nd:YAG solid state 355 nm ultraviolet laser is reported by using intra cavity double frequency and sum frequency mixing. The Nd:YAG crystal is sidepumped by a LD, the intra cavity green radiation is generated using a type I non- critical phase matched littium triborate (LBO) and subsequent frequency mixing in two type II LBO crystals. A high power and high repetition rate 355 nm ultraviolet laser is obtained by sum frequency mixing back and forth. The output power of 15.3 W at 355 nm is obtained at the pump power of 939.6 W and repetition frequency of 8 kHz with pulse width as short as 90 ns. The conversion efficiency is 1.63%. The beam quality M2x, M2y is 4.33 and 4.56, respectively, and the degree of power instability is ±2.7%..
Laser & Optoelectronics Progress
- Publication Date: Jul. 02, 2014
- Vol. 51, Issue 8, 81401 (2014)
Experimental Investigation of Adjacent-Frame Similarity of Bidirectional Optical Fiber Ring Chaotic Laser
Qin Haijuan, Fang Nian, Wang Lutang, Huang Zhaoming, and Wu Chunxu
The output waveforms of a bidirectional optical fiber chaotic ring laser based on semiconductor optical amplifier (SOA) present frame structures. The adjacent-frame waveforms have the characteristic of similarity, which declines when the laser suffers an external disturbance. In order to obtain waveforms with high simiThe output waveforms of a bidirectional optical fiber chaotic ring laser based on semiconductor optical amplifier (SOA) present frame structures. The adjacent-frame waveforms have the characteristic of similarity, which declines when the laser suffers an external disturbance. In order to obtain waveforms with high similarity and good consistency for accurate detection of disturbances, experimental investigations on various factors which can affect the adjacent-frame similarity of the laser are carried out, including the performances and drive current of SOAs, symmetry of system structure, output coupling ratios and optical fiber ring lengths. The similarity levels are investigated by the mean values of the adjacent-frame cross-correlation peaks. The consistency degrees are measured by the maximum deviation of the peaks. The results show that the booster optical amplifier (BOA) with the polarization-maintaining property is the most suitable active device. The bigger the drive current, the better the adjacent-frame similarity. By only adjusting polarization controller to make the output chaotic waveform look like sine signal with continuous narrow-band spectrum, the symmetry of system structure, coupling ratios and optical fiber ring lengths will not affect the adjacent-frame similarity. However, the ring lengths affect the system sensitivity. Moreover, the system stability is also investigated. The adjacentframe similarity fluctuates at 10-3 level within about five minutes..
Laser & Optoelectronics Progress
- Publication Date: Jul. 21, 2014
- Vol. 51, Issue 8, 81402 (2014)
Relaxation of Residual Stress on Laser-Peened Surface during Cyclic Loading
Tian Qing, Zhou Jianzhong, Huang Shu, Sheng Jie, Meng Xiankai, Dai Lei, and Zhu Weili
In order to investigate the relaxation rule of residual stress on laser-peening surface of 6061-T6 aluminum alloy during cyclic loading, laser-peening treatment and thermal insulation of 6061-T6 aluminum alloy has been carried out and the surface residual stress under different cyclic stress levels and circle times hasIn order to investigate the relaxation rule of residual stress on laser-peening surface of 6061-T6 aluminum alloy during cyclic loading, laser-peening treatment and thermal insulation of 6061-T6 aluminum alloy has been carried out and the surface residual stress under different cyclic stress levels and circle times has been determined. The results show that most of the relaxation of residual stress occurs during the first 10 to 100 cycles, and the stress intends to be steady after 1000 cycles. Larger cyclic loading can cause greater value and rate of residual stress relaxation and even lead to complete release, especially when the peak stress is close to the yield stress. In addition, surface residual stress of the laser-peening specimens treated at 150 ℃ for 10 min is reduced and the magnitude and rate of the stress relaxation are lower. The stability of residual stress during cyclic loading is improved..
Laser & Optoelectronics Progress
- Publication Date: Jun. 27, 2014
- Vol. 51, Issue 8, 81403 (2014)
Analysis of Approximate Conditions and Error of Trapping Forces in a Fiber Optical Trap
Xiong Wei, Xiao Guangzong, Han Xiang, Zhang Yaokai, Huang Yun, and Luo Hui
Fiber optical tweezers capture and control particles with fiber output beam. The fast development of fiber optical tweezers puts forward higher requirements to the theoretical study of trapping forces. Numerical simulation of trapping forces of Mie particle whose diameter is larger than the free-space wavelength is donFiber optical tweezers capture and control particles with fiber output beam. The fast development of fiber optical tweezers puts forward higher requirements to the theoretical study of trapping forces. Numerical simulation of trapping forces of Mie particle whose diameter is larger than the free-space wavelength is done, the approximate conditions in trapping forces calculating and its applied range are discussed, the result of direct calculating and the result calculated under the approximate conditions are obtained and compared. Influence on approximate calculating caused by the distance between particle and fiber end is analyzed. The numerical results show that when the distance between particle and fiber end is larger than a certain value d, which is related to radius of waist beam, some angle parameters such as the incidence angle and the azimuthal angle can be approximated, and the conclusion provides theoretical reason for simplified fiber optical trapping force calculating..
Laser & Optoelectronics Progress
- Publication Date: Jul. 23, 2014
- Vol. 51, Issue 8, 81404 (2014)
Research of Coaxial Powder Stream Field in Laser Manufacturing
Liu Lifeng, Dong Liying, Dong Ling, and Wang Yunshan
Distribution of powder stream from coaxial nozzle directly affects the quality and accuracy of the parts by laser manufacturing. The convergent distribution of powder flow and powder convergent performance is researched. A theoretical model of coaxial powder nozzle is established. And a detecting system of powder streaDistribution of powder stream from coaxial nozzle directly affects the quality and accuracy of the parts by laser manufacturing. The convergent distribution of powder flow and powder convergent performance is researched. A theoretical model of coaxial powder nozzle is established. And a detecting system of powder stream field is developed to real- time measure morphology and concentration distribution of powder stream. The results show that the simulations of the powder flow agree well with the experimental measurements. The systemic studies on the behaviors of powder stream morphology and concentration distribution of powder stream help to optimize the design of coaxial powder feeding head and control laser manufacturing better..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2014
- Vol. 51, Issue 8, 81405 (2014)
Materials
Impact of the Ratio Between Solar Mask Window Width and Electrode Width on the Performance of Light-Generated Current
Wang Qiang, Xu Ying, and Hua Guoran
An efficient process design parameter T, the width ratio of the selective diffusion mask window and the electrode, is presented. The results show that there always exists an optimum T value for different substrate concentrations and doping concentrations to obtain the maximum short-circuit current. As the selective dopAn efficient process design parameter T, the width ratio of the selective diffusion mask window and the electrode, is presented. The results show that there always exists an optimum T value for different substrate concentrations and doping concentrations to obtain the maximum short-circuit current. As the selective doping concentration is 1×1018~1×1019 cm-3, the optimal T value is 1; when the selective doping concentration is 1 × 1020 cm-3 , the optimal T value is less than 0.5. Increase of the electrode width makes the photocurrent decrease, but it has little effect on the optimal T value. Increasing the selective doping concentration causes decrease of the optimal T value..
Laser & Optoelectronics Progress
- Publication Date: Jul. 21, 2014
- Vol. 51, Issue 8, 81601 (2014)
Optical Design and Fabrication
Optical Fabrication on High Volume Fraction SiCp/Al Coating Nikel-Cobalt Alloy Paraboloid Mirror
Fan Di
In order to manufacture mirrors with fine mechanical and thermodynamic properties, the fabrication of high volume fraction SiCp/Al coating nickel- cobalt alloy aspheric mirror is studied; the mechanical and thermodynamic properties of high volume fraction SiCp/Al are introduced; then, several kinds of polish agent and In order to manufacture mirrors with fine mechanical and thermodynamic properties, the fabrication of high volume fraction SiCp/Al coating nickel- cobalt alloy aspheric mirror is studied; the mechanical and thermodynamic properties of high volume fraction SiCp/Al are introduced; then, several kinds of polish agent and model are used in experiments for polishing SiCp/Al coating nickel- cobalt alloy samples; finally, on the basis of experiments, a Φ300 mm high volume fraction SiCp/Al coating nickel- cobalt alloy paraboloid mirror is manufactured. The tested results indicate that surface accuracy of the mirror is 0.027 λ (RMS, λ =632.8 nm), and the surface roughness is 2.1 nm (Ra)..
Laser & Optoelectronics Progress
- Publication Date: Jul. 16, 2014
- Vol. 51, Issue 8, 82201 (2014)
Intergrated Opto-Mechanical Analysis of a Long-Focus Airborne Camera under Overloads
Xu Yulei, Tian Haiying, and Liu Jian
The deformation of opto-mechanical system caused by environmental load should have a serious influence on the performance of the airborne camera. In order to evaluate this influence, an effective technique for intergrated opto-mechnical analysis is required. The finite element model of the airborne camera is establisheThe deformation of opto-mechanical system caused by environmental load should have a serious influence on the performance of the airborne camera. In order to evaluate this influence, an effective technique for intergrated opto-mechnical analysis is required. The finite element model of the airborne camera is established and the static analysis is accomplished. Under the given environmental loads, including heading acceleration, spanwise acceleration and normal acceleration, simulation and analysis are carried out on the deformation of the structure of airborne camera, especially on the deformation of the lens caused by environmental loads and the support structure. Zernike polynomial is used as an interface tool to fit deformed mirror surface and Zernike coefficients are substituted into optical design software for the intergrated optomechanical analysis. The influence of the given environmental loads on optical performance is evaluated. The analysis results show that under the given environmental loads the modulation transfer functions (MTF) of airborne camera′ s optical system in all fields of views are not less than 0.16 with spatial frequency from 0 to 62.5 cycle/mm, which can meet the image quality demand under the given environmental loads..
Laser & Optoelectronics Progress
- Publication Date: Jul. 03, 2014
- Vol. 51, Issue 8, 82202 (2014)
Remote Sensing and Sensors
Surface Plasmon Resonance Biosensor for Rapid Unmarked Coumaphos Detection
Qi Pan, Ma Xiao, Zhong Jingang, and Li Ying
The self-developed portable surface plasmon resonance biosensor is used in the detection of highly toxic pesticide coumaphos, as the existing pesticide detection methods are complicated, with precious instrument, and not conductive to on-site rapid detection. The antibody direct detection experiments are conducted; theThe self-developed portable surface plasmon resonance biosensor is used in the detection of highly toxic pesticide coumaphos, as the existing pesticide detection methods are complicated, with precious instrument, and not conductive to on-site rapid detection. The antibody direct detection experiments are conducted; the continuous detection method is proposed and preceded in small coumaphos molecules with concentrations of 500, 200, 100, 50 and 0 mg/L. The validity of this method and the device is demonstrated by experiments. The unmarked coumaphos detection method based on the surface plasmon resonance is simple. The developed device is portable and easy to operate. The rapid and real-time detection can be realized by this method..
Laser & Optoelectronics Progress
- Publication Date: Jul. 18, 2014
- Vol. 51, Issue 8, 82801 (2014)
Reviews
Research Progress of Optical Waveguide Phased Array Scanner
Jin Yadong, Yan Aimin, Hu Zhijuan, Zhang Hao, and Lü Congling
The technology of optical phased array is well known for its flexibility, high speed and accurate beam scanning. This technology is used in the new systems of laser radar, space laser communications and other important related applications. This paper reviews the research progress of optical waveguide phased array techThe technology of optical phased array is well known for its flexibility, high speed and accurate beam scanning. This technology is used in the new systems of laser radar, space laser communications and other important related applications. This paper reviews the research progress of optical waveguide phased array technology and introduces the latest research progress of optical phased array based on LiNbO3, GaAs/AlGaAs, InP, and silicon-on-insulator materials in detail. We also discuss the characteristics and advantages of the optical waveguide phased array. The applications in laser scanning imaging, laser radar, laser displays, optical switches, laser printing and other military and civilian areas are discussed. Finally, the development prospect of the optical waveguide phased array technology is proposed..
Laser & Optoelectronics Progress
- Publication Date: Jul. 02, 2014
- Vol. 51, Issue 8, 80002 (2014)
Spectroscopy
Quantitative Analysis of Pb in Solution by Comparing Integrated ICCD Single and Double Pulse LIBS
Yang Ping, Huang Lin, Yao Mingyin, Chen Tianbing, He Xiuwen, Li Wenbing, Zheng Jianhong, Hu Huiqin, and Liu Muhua
Lower detection stability and sensitivity of laser-induced breakdown spectroscopy (LIBS) restrict development of the technique. We use an integrated ICCD single and double pulse LIBS system to analyze the Pb element in Pb(NO3)2 solution enriched by the filter paper, to compare the sampling gate width, integral time delLower detection stability and sensitivity of laser-induced breakdown spectroscopy (LIBS) restrict development of the technique. We use an integrated ICCD single and double pulse LIBS system to analyze the Pb element in Pb(NO3)2 solution enriched by the filter paper, to compare the sampling gate width, integral time delay, time delay of two double pulse laser beams and other parameters affecting the spectrum quality, and to determine the best conditions to detect Pb element in water solution by LIBS. The results show that the double pulse has better stability. Under the optimal conditions, the single, double pulse LIBS spectral information of six solution samples with different Pb concentrations is obtained, and the relationship model between the actual Pb concentration and its spectral intensity is built, showing that the LIBS detection limits of trace Pb element are 15.95 μg /mL and 5.48 μg /mL, respectively. The fitting results indicate that the double pulse has a better linear correlation coefficient, detection sensitivity and accuracy. It is suggested that the integrated ICCD dual-pulse LIBS will improve the effect on heavy metal detection in water..
Laser & Optoelectronics Progress
- Publication Date: Jul. 16, 2014
- Vol. 51, Issue 8, 83001 (2014)
Ultrafast Optics
Self-Generated Magnetic Field in the Interaction of Ultraintense Laser-Plasma Slab Target
Abuduresuli, Aierken Zakeer, and Palihati Mijiti
In order to investigate the mechanism of formation of self-generated magnetic field in laser plasma interaction, the self-generated magnetic field was theoretically analyzed and numerically simulated. Using kinetic theory here the self generated magnetic field is generated by the nonparallelism of the temperature gradiIn order to investigate the mechanism of formation of self-generated magnetic field in laser plasma interaction, the self-generated magnetic field was theoretically analyzed and numerically simulated. Using kinetic theory here the self generated magnetic field is generated by the nonparallelism of the temperature gradient and density gradient when the intense laser injected to the thin plasma target. The time evolution relation of the spatial distribution of the self generated magnetic field is obtained. The results show that when laser injected the plasma target, self generated magnetic field is generated on the surface of the plasma. Because of the nonparallel density gradient and the temperature gradient, this magnetic field considerably affects the absorption of laser and various transmission processes of laser..
Laser & Optoelectronics Progress
- Publication Date: Jul. 23, 2014
- Vol. 51, Issue 8, 83201 (2014)
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