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Record 133 of
Title:Modeling and simulation of effect of optical distortion on the large aperture static imaging spectrometer
Author(s):Lü, Qun-Bo(1); Xiangli, Bin(1,2); Yao, Tao(1,3); Jing, Juan-Juan(1); Wang, Zhong-Hou(1)
Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 30 Issue: 1 DOI: 10.3964/j.issn.1000-0593(2010)01-0142-04 Published: January 2010
Abstract:As a new type Fourier transform imaging spectrometry, large aperture static imaging spectrometry (LASIS) has come forth in recent years, which has many advantages such as simple principle, high stability and so on. However, the requirement for the optical system design of LASIS was very harsh. As one of the optical aberrations, optical distortion degrades the data quality acquired by LASIS, consequently limits its applications. According to the analysis of the data acquisition principle of LASIS, the data model with the effect of optical distortion was presented, which could be used for LASIS performance pre-evaluation. Finally, the computer simlulation of the data model was achieved with supposed parameters. The simulation results indicated that the relative error more than 5% was induced in the recovery spectrum, and approximate 8 nm spectral line deviation was occurred at the long wavelength region. The results show that the 4% optical distortion was inapplicable for LASIS although it is acceptant for common optical imaging system.
Accession Number: 20100312640939
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Record 134 of
Title:Paraxial propagation properties of waveguide modes in single-mode fiber
Author(s):Chen, Youjie(1,2); Duan, Kailiang(2); Lü, Baida(1); Zhao, Wei(2)
Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams Volume: 22 Issue: 2 DOI: 10.3788/HPLPB20102202.0257 Published: February 2010
Abstract:By expanding the LP01 mode into a linear superposition of Laguerre-Gaussian modes and using Collins formula, the analytical propagation equation of wave-guide modes in a single-mode fiber through paraxial ABCD optical systems is derived. The free-space propagation and focusing properties of the LP01 mode are studied and compared with those of the fundamental Gaussian mode. It is shown that the Gaussian mode in place of the LP01 mode may introduce some errors. In the focused field of the LP01 mode there exists the focal shift which increases with decreasing Fresnel number. By a suitable choice of the Fresnel number, a long focusing depth may appear for the LP01 mode which is quite different from that of the focused Gaussian mode.
Accession Number: 20101612868308
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Record 135 of
Title:All-fiber mode-locked nanosecond laser employing intracavity chirped fiber gratings
Author(s):Wang, Hushan(1); Wang, Yishan(1); Zhao, Wei(1); Zhang, Wei(1); Zhang, Ting(1); Hu, Xiaohong(1); Yang, Zhi(1); Liu, Hongjun(1); Duan, Kailiang(1); Liu, Xuemin(1); Li, Cheng(1); Shen, Deyuan(1); Sui, Zhan(2); Liu, Bin(3,4)
Source: Optics Express Volume: 18 Issue: 7 DOI: 10.1364/OE.18.007263 Published: March 29, 2010
Abstract:We demonstrate that nanosecond pulses are generated directly from an all-fiber mode-locked ytterbium-doped fiber laser. A pair of Chirped Fiber Gratings (CFGs) with different sign of dispersion is employed for intracavity dispersion management. Self-starting stabilized mode-locking operation is achieved by nonlinear polarization evolution (NPE). The 1.27 ns pulses are obtained after one CFG with large positive dispersion. The pulse energy is up to 15 nJ at a repetition rate of 3.48 MHz. ? 2010 Optical Society of America.
Accession Number: 20101412822668
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Record 136 of
Title:Double differential cross sections of light charged particle emission in neutron induced reactions on 54,56,57,58Fe
Author(s):Zhang, Zhengjun(1,2); Han, Yinlu(3); Cai, Chonghai(4)
Source: Annals of Nuclear Energy Volume: 37 Issue: 2 DOI: 10.1016/j.anucene.2009.11.013 Published: February 2010
Abstract:The energy spectra and double differential cross sections of the light composite particle (deuteron, triton, helium and alpha-particle) emissions for n + 54,56,57,58Fe reaction are studied by integrating the optical model, the intra-nuclear cascade model, direct reaction theories, equilibrium reaction theory and the exciton model which included the improved Iwamoto-Harada model. Theoretical calculated results are compared with existing experimental data. ? 2009 Elsevier Ltd. All rights reserved.
Accession Number: 20100312639786
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Record 137 of
Title:Spectrum recovery method for interferometric data
Author(s):Lü, Qun-Bo(1); Yao, Tao(1,3); Xiangli, Bin(1,2); Huang, Min(1,3)
Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 30 Issue: 1 DOI: 10.3964/j.issn.1000-0593(2010)01-0114-04 Published: January 2010
Abstract:The interferometric data acquired by Fourier transform spectrometer was a betweenness which couldn't be used directly. For the successful application of the interferometric data, spectrum recovery processing must be adopted. The conventional method based on inverse Fourier transform was frequently used for spectrum recovery. According to the principle analysis of the interferometric data, the mixing model was induced, and the spectrum recovery method based on the mixing model of the interferometric data was presented. Finally, the computer simulation for these two methods mentioned above was implemented, and the recovered spectra were compared with the standard spectrum. The simulation results indicated that the spectral precision of the new method was better than the conventional method, which provided a new scheme for spectrum recovery.
Accession Number: 20100312640933
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Record 138 of
Title:Comparison of two types of fourier transform imaging spectrometry
Author(s):Xiangli, Bin(1); Lü, Qun-Bo(1); Huang, Min(1,3); Yao, Tao(2,3)
Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 30 Issue: 5 DOI: 10.3964/j.issn.1000-0593(2010)05-1422-05 Published: May 2010
Abstract:The comparison between "large aperture static imaging spectrometry (LASIS)" designed by author and "method for simultaneously measuring the spectral intensity as a function of wavelength of all the pixels of a two dimensional scene" (MSMSI) designed by Israeli researchers is given. The difference of the interferometers and imaging systems in LASIS and MSMSI is discussed. The nonlinear curve of optical path difference of MSMSI is simulated. Inspired by the operation of MSMSI, the time modulated Fourier transform imaging spectrometry based on lateral shearing interferometer was presented. The optical path differences of different field of view were given under the condition of regularly rotating the lateral shearing interferometer.
Accession Number: 20102212974714
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Record 139 of
Title:The analysis of the wavefront aberration caused by the gravity of the tunable-focus liquid-filled membrane lens
Author(s):Zhang, Wei(1,2); Liu, Pengfei(1); Wei, Xiaona(1); Zhuang, Songlin(1); Yang, Bo(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7849 Issue: DOI: 10.1117/12.869866 Published: 2010
Abstract:Liquid lens is a novel optical device which can implement active zooming. With liquid lens, zoom camera can be designed with more miniature size and simpler structure than before. It is thought that the micro zoom system with liquid lens has a very wide potential applications in many fields, in which the volume and weight of the system are critically limited, such as endoscope, mobile, PDA and so on. There are mainly three types of tunable-focus liquid lens: liquid crystal lens, electrowetting effect based liquid lens and liquid-filled membrane lens. Comparing with the other two kinds of liquid lens, the liquid-filled membrane lens has the advantages of simple structure, flexible aperture and high zooming efficiency. But its membrane surface will have an initial shape deformation caused by the gravity when the aperture of the lens is at large size, which will lead to the wave front aberration and the imaging quality impairing. In this paper, the initial deformation of the lens caused by the gravity was simulated based on the theory of Elastic Mechanics, which was calculated by the Finite Element Analysis method. The relationship between the diameter of the lens and the wave front aberration caused by the gravity was studied. And the Optical path difference produced by different liquid density was also analyzed. ? 2010 Copyright SPIE - The International Society for Optical Engineering.
Accession Number: 20110113551061
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Record 140 of
Title:Robust tensor analysis with L1-norm
Author(s):Pang, Yanwei(1); Li, Xuelong(2); Yuan, Yuan(3)
Source: IEEE Transactions on Circuits and Systems for Video Technology Volume: 20 Issue: 2 DOI: 10.1109/TCSVT.2009.2020337 Published: February 2010
Abstract:Tensor analysis plays an important role in modern image and vision computing problems. Most of the existing tensor analysis approaches are based on the Frobenius norm, which makes them sensitive to outliers. In this paper, we propose L1-norm-based tensor analysis (TPCA-L1), which is robust to outliers. Experimental results upon face and other datasets demonstrate the advantages of the proposed approach. ? 2006 IEEE.
Accession Number: 20100712719221
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Record 141 of
Title:Yb3+-doped 200 μm diameter core, gain guided index-antiguided fiber
Author(s):Lu, M.(1); Li, W.(1); Zou, K.(1); Dai, S.(1); Wei, W.(1,2); Peng, B.(1,2)
Source: Applied Physics B: Lasers and Optics Volume: 98 Issue: 2-3 DOI: 10.1007/s00340-009-3737-z Published: February 2010
Abstract:The lasing in an end-pumped gain guided index-antiguided (GG-IAG) Yb 3+-doped silicate glass fiber with a 200 μm diameter core is demonstrated. Laser beams with similar beam propagation factors M 2 and mode field diameters W 0 (>160 μm) were observed at the output end of the GG-IAG fibers under different pump powers, which indicated that single mode behavior and excellent beam quality were achieved during propagation. Furthermore, the laser amplifier characteristics in the present Yb3+-doped GG-IAG fiber were also evaluated. ? 2009 Springer-Verlag.
Accession Number: 20100212634113
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Record 142 of
Title:An improved hyperspectral classification algorithm based on pixel spatial association
Author(s):Gao, Xiaohui(1,2); Wei, Ruyi(1,2); Wei, Junxia(1,2); Zhou, Jinsong(3); Yu, Tao(1)
Source: Proceedings - 2010 3rd International Congress on Image and Signal Processing, CISP 2010 Volume: 2 Issue: DOI: 10.1109/CISP.2010.5646886 Published: 2010
Abstract:Classification algorithm is an important technique that has been studied for many years in hyperspectral image processing along with the development of hyperspectral remote sensing. Traditional classification algorithms mostly focus on the differences of spectral dimension but neglecting spatial structures of geography objects. By improving the ECHO algorithm, we put forward a classification algorithm based on pixel's spatial association. This algorithm could possibly be used as an important step in hyperspectral data classification and identification. It may also be a good approach to get rid of redundancy information in endmember extracting, which means that pure spectrum can be extracted from less pixels in the hyperspectral image. In this way, endmember extracting and spectral unmixing will take less time and become more efficient. ?2010 IEEE.
Accession Number: 20105213529852
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Record 143 of
Title:Synthesis and properties of Eu3+-doped strontium fluoroapatite nanocrystals by low-temperature hydrothermal method
Author(s):Liu, Yanni(1); Yu, Changhai(1); Zhang, Wei(1); Li, Jinjiang(1); Peng, Bo(2); Wei, Wei(1)
Source: Optoelectronics and Advanced Materials, Rapid Communications Volume: 4 Issue: 4 DOI: Published: April 2010
Abstract:A novel of Eu3+-doped strontium fluoroapatite nanocrystals(Eu3+: Sr10(PO4)6F2 or Eu3+:S- FAP) were firstly prepared by a low-temperature hydrothermal method, using ethylenediam- inetetraacetic acid disodium (Na2H2EDTA) as capping agent. Their morphology and structure were characterized by TEM, XRD and FTIR spectra. The results revealed that the nanocrystals mainly took on spherical-like shape and were well crystalline with an average diameter of less than 80 nm. Photoluminescence spectra indicated that the nanocrystals had high luminescence intensity ratio (R/O) of 5D0→7F2 to 5D0→7F1 transitions and high quenching concentration. They are promising materials for the applications of laser, display, and sensors.
Accession Number: 20203409076374
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Record 144 of
Title:Methods for nonlinear optic path difference of reflecting rotating fourier transform spectrometer
Author(s):Jing, Juan-Juan(1,2); Zhou, Jin-Song(3); Xiangli, Bin(3); Lü, Qun-Bo(3); Wei, Ru-Yi(1,2)
Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 30 Issue: 6 DOI: 10.3964/j.issn.1000-0593(2010)06-1678-05 Published: June 2010
Abstract:The principle of reflecting rotating Fourier transform spectrometer was introduced in the present paper. The nonlinear problem of optical path difference (OPD) of rotating Fourier transform spectrometer universally exists, produced by the rotation of rotating mirror. The nonlinear OPD will lead to fictitious recovery spectrum, so it is necessary to compensate the nonlinear OPD. Three methods of correction for the nonlinear OPD were described and compared in this paper, namely NUFFT method, OPD replace method and interferograms fitting method. The result indicates that NUFFT was the best method for the compensation of nonlinear OPD, OPD replace method was better, its precision was almost the same as NUFFT method, and their relative error are superior to 0.13%, but the computation efficiency of OPD replace method is slower than NUFFT method, while the precision and computation efficiency of interferograms fitting method are not so satisfied, because the interferograms are rapid fluctuant especially around the zero optical path difference, so it is unsuitable for polynomial fitting, and because this method needs piecewise fitting, its computation efficiency is the slowest, thus the NUFFT method is the most suited method for the nonlinear OPD compensation of reflecting rotating Fourier transform spectrometer.
Accession Number: 20102513030998
