2010
2010
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Record 277 of
Title:Experimental study on high power all-fiber laser
Author(s):Zhao, Baoyin(1,2); Duan, Kailang(1); Zhao, Wei(1); Li, Cheng(1); Wang, Yishan(1)Source: Chinese Optics Letters Volume: 8 Issue: 4 DOI: 10.3788/COL20100804.0404 Published: April 2010Abstract:A high power all-fiber laser is experimentally studied. A monolithic fiber laser system with only one stage of resonator cavity is constructed and 404-W continuous wave (CW) output power is obtained. Its optical-to-optical conversion efficiency is up to 64%. The laser central wavelength is at 1081 nm with the spectral full-width at half-maximum (FWHM) of 2 nm. The laser setup can work with excellent stability; in the long time of high power operation, no thermal distortions or damages are observed. ? 2010 Chinese Optics Letters.Accession Number: 20102212974291 -
Record 278 of
Title:Novel method to examine phase object by the use of TFT-LCD
Author(s):Guo, Rongli(1,2,3); Yao, Baoli(2); Han, Jun(1); Yu, Xun(1); Nie, Liang(1); Duan, Cunli(1); Wang, Fan(4)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7656 Issue: PART 1 DOI: 10.1117/12.866452 Published: 2010Abstract:A novel method of using Thin Film Transistor-Liquid Crystal Display(TFT-LCD) as phase filter in Zernike phase contrast method is introduced. First, theoretical analysis of using TFT-LCD as programmable phase modulator instead of conventional phase contrast plate to filter the spectrum is conducted. Then the phase modulation property curve of the used TFT-LCD is measured which is function of gray scales in modified Mach-Zehnder interferometer, and frequency filtering is used to eliminate interferogram's noise and the correlation method is adopted to determine the mini-displacement of interference fringe. At last, Experiment conducted in 4F system. The result showed that the method is effective in qualitative observation of phase distribution for a small phase object. ? 2010 Copyright SPIE - The International Society for Optical Engineering.Accession Number: 20105013487535 -
Record 279 of
Title:Parallel phase-shifting interferometry based on michelson-like architecture
Author(s):Min, Junwei(1,2); Yao, Baoli(1); Gao, Peng(1); Guo, Rongli(1); Zheng, Juanjuan(1); Ye, Tong(1)Source: Applied Optics Volume: 49 Issue: 34 DOI: 10.1364/AO.49.006612 Published: December 1, 2010Abstract:In this paper, we present a new scheme for parallel phase-shifting interferometry that employs a Michelson-like architecture and a simple polarization unit to generate two phase-shifting interferograms with phase shift of π/2 at a single camera exposure. The parallel phase-shifting unit is built with simple optical components, and the distance between the parallel interferograms can be adjusted conveniently. Phase reconstruction is performed by using an algorithm developed for two-step phase-shifting interferometry. The practicability of the proposed configuration and the reconstruction method is demonstrated by experiments. ? 2010 Optical Society of America.Accession Number: 20105213522320 -
Record 280 of
Title:Photon counting imaging UV detector based on Vernier anode
Author(s):Yan, Qiurong(1,2); Zhao, Baosheng(1); Liu, Yong'an(1); Yang, Hao(1,2); Sheng, Lizhi(1,2)Source: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: Issue: DOI: 10.1016/j.nima.2010.10.082 Published:Abstract:The long slit spectrograph is one of the instruments onboard WSO-UV, a multi-national space astronomy project led by Russia. According to the report, both the FUV and the NUV channels of LSS choose the MCP detector in the focal plane and the detector will be read out using the charge induction technique. According to the desired performance, Vernier anode will be one of the optimum readout schemes. In this paper, the structure and parameters of FUV and NUV detectors have been basically determined. The decode principle and design of Vernier anode are introduced in detail. Preliminary experimental results show that decoding algorithm and design of Vernier anode are correct and reveal a spatial resolution superior to 100 μm according to the resolution test results. Ways to improve the imaging performance were proposed. ? 2010 Elsevier B.V. All rights reserved.Accession Number: IP51149356 -
Record 281 of
Title:Measurement of optical trapping force and stiffness of micro-particles with the drag-force method
Author(s):Peng, Fei(1,2); Yao, Bao-Li(1); Lei, Ming(1); Yan, Shao-Hui(1)Source: Guangdianzi Jiguang/Journal of Optoelectronics Laser Volume: 21 Issue: 1 DOI: Published: January 2010Abstract:By using the hydrodynamic method, maximal transverse trapping forces on three kinds of micro-particles with radii ranging from 0.5 μm to 22 μm were measured by dragging these transparent dielectric beads suspended in water with the focused laser beam. The magnitude of trapping forces obtained from the experiment was of the order of pico-Newton. For PMMA particles of large size, the offset Δx of the particle from the optical trapping center was measured with different dragging velocities, and the trap stiffness was calculated according to the experimental result. In addition, at the edge of optical trap, where Δx is larger than the radius of the micro-particle, the optical trapping force was also measured to obtain the domain of trapping force and the relationship between the force and Δx. Comparison of measured trapping forces and stiffness on yeast cells with different radii under the same condition shows that the critical velocity decreases, the maximal trapping force rises and the stiffness reduces with increase of the radius of the yeast cell.Accession Number: 20101212786712 -
Record 282 of
Title:Influence of annealing temperature on the performance of Ge film and photon-counting imaging system
Author(s):Zhao, Feifei(1,2); Zhao, Baosheng(1); Sai, Xiaofeng(1); Zhang, Xinghua(1,2); Wei, Yonglin(1); Zou, Wei(1)Source: Chinese Optics Letters Volume: 8 Issue: 4 DOI: 10.3788/COL20100804.0361 Published: April 2010Abstract:Compared with the traditional image intensifier with phosphor screen readout, the photon-counting imaging detector with charge induction readout is more beneficial in several aspects (e.g., good imaging properties and time resolution) to astronomy, reconnaissance, bioluminescence, and materials research. However, the annealing temperature during the tube-making process can affect the properties of the Ge film, and consequently impair the performance of the detector. Therefore, the influence of annealing temperature on Ge film and on the detector is studied in order to determine the crucial parameters. The Ge films are prepared on ceramic and quartz glass by the use of an electron gun. They are analyzed by scanning electron microscope (SEM), high-resistance meter, and X-ray diffraction (XRD). The results show that the optimum substrate and annealing temperature are ceramic plate and 250°C, respectively. ? 2010 Chinese Optics Letters.Accession Number: 20102212974279 -
Record 283 of
Title:An all fiber laser for distributed optical fiber sensor
Author(s):Gao, Cunxiao(1); Zhu, Shaolan(1,2); Feng, Li(1); Song, Zhiyuan(1,2); Cao, Zongying(1); He, Haodong(1); Niu, Linquan(1,2)Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 37 Issue: 6 DOI: 10.3788/CJL20103706.1501 Published: June 2010Abstract:An all fiber laser which is suitable for distributed optical fiber sensor is reported. The laser is based on the technique of master-oscillator-power-amplifier (MOPA), whose seed laser is a laser diode and amplifier is Er3+ doped fiber amplifier. The laser operates in wavelength of 1550 nm with the tunable repetition rate and the pulsewdith, and the 3 dB width is less than 0.2 nm. The maximum peak power 1.1 kW of laser pulse is obtained, and the power of amplified spontaneous emission (ASE) in the output pulse is less than 10% in all condition.Accession Number: 20102713063577 -
Record 284 of
Title:Chinese text detection and location for images in multimedia messaging service
Author(s):Yan, Jianqiang(1); Tao, Dacheng(2); Tian, Chunna(1); Gao, Xinbo(1); Li, Xuelong(3)Source: Conference Proceedings - IEEE International Conference on Systems, Man and Cybernetics Volume: Issue: DOI: 10.1109/ICSMC.2010.5641748 Published: 2010Abstract:Text detection and recognition for images in multimedia messaging service is a very important task. Since Chinese characters are composed of four kinds of strokes, i.e., horizontal line, top-down vertical line, left-downward slope line and short pausing stroke, we present Gabor filters with scale and direction varied to describe the strokes of Chinese characters for candidate text area extraction. By establishing four sub-neural networks to learn the texture of text area, the learnt classifiers are used to detect candidate text areas. Experimental results show that the proposed approach can improve the accuracy of text detection and the recognition rate of images in multimedia messaging service. ?2010 IEEE.Accession Number: 20110413608161 -
Record 285 of
Title:Algorithm for extended X-ray image dynamic range based on image fusion
Author(s):Li, Wei(1); Hou, Qing(2); Li, Hanzhi(3)Source: 3rd International Symposium on Test Automation and Instrumentation, ISTAI 2010 Volume: Issue: DOI: Published: 2010Abstract:An algorithm of X-ray image extended dynamic range based on the image fusion is presented in the paper. First of all, the X-ray original image are processed by wavelet decomposition with defined layers. The generated high frequency wavelet and low frequency wavelet are processed by two different kinds of methods respectively, then the wavelets in every frequency band inverse transformed to image fusion. With a final step of histogram equalization, it comes out an expanded dynamic range, compared with original image.Accession Number: 20142017724890