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Record 61 of
Title:Determination of dispersion and nonlinear coefficients of photonic crystal fibers by degenerated FWM method
Author(s):Ge, Wenping(1,2); Lin, Aoxiang(1,3); Guintrand, Cyril(1); Toulouse, Jean(1)
Source: Optics InfoBase Conference Papers Volume: Issue: DOI: Published: 2010
Abstract:By using degenerated four wave mixing (FWM) method and counting the efficiency of the newly created frequency, we easily obtained dispersion, dispersion slope and nonlinear coefficients by fitting the experimental data with several well-known functions. ? 2010 Optical Society of America.
Accession Number: 20140817363773
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Record 62 of
Title:Optical system design of space sensor with two long focal length lens
Author(s):He, Yinghong(1); Ma, Zhen(1); Zhao, Baochang(1); Chang, Lingying(1); Chen, Liwu(1); Ma, Xiaolong(1); Yi, Hongwei(1)
Source: Guangxue Xuebao/Acta Optica Sinica Volume: 30 Issue: 10 DOI: 10.3788/AOS20103010.3027 Published: October 2010
Abstract:A compact space optical system without moving parts which can get two focal lengths is designed. Ritchey-Chrétien (R-C) mirror is common for long-focus system and short-focus system. A splitter prism is used for splitting the light into two beams relayed by transmitting optical system. The focal length is 4700 mm and F number is 13.4 for the long-focus system, and the focal length is 2350 mm and F number is 6.7 for the short-focus system. Some measure is taken to make sure the less degradation of MTF for thermal distortion, such as a kind of material with small thermal expansion using comrection between the primer mirror and the second mirror and material with good thermal property as mirror substrate for reduce surface distortion. The modulation transfer function (MTF) of optical system in condition of (19±3)°C is analyzed, which shows a good result for user 's requirement.
Accession Number: 20104613383574
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Record 63 of
Title:Phase-shifting point-diffraction interferometry with common-path and in-line configuration for microscopy
Author(s):Gao, Peng(1,2,3,4); Harder, Irina(2); Nercissian, Vanusch(1); Mantel, Klaus(2); Yao, Baoli(3)
Source: Optics Letters Volume: 35 Issue: 5 DOI: 10.1364/OL.35.000712 Published: March 1, 2010
Abstract:A new common-path and in-line point-diffraction interferometer for quantitative phase microscopy is proposed. The interferometer is constructed by introducing a grating pair into the point-diffraction interferometer, thus forming a common-path and in-line configuration for object and reference waves. Achromatic phase shifting is implemented by linearly moving one of the two gratings in its grating vector direction. The feasibility of the proposed configuration is demonstrated by theoretical analysis and experiments. ? 2010 Optical Society of America.
Accession Number: 20101012751460
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Record 64 of
Title:Static simulation experiment of image motion measurement based on optical joint transform correlator
Author(s):Yi, Hongwei(1); Zhao, Hui(1); Wen, Desheng(1); Li, Yingcai(1)
Source: Guangxue Xuebao/Acta Optica Sinica Volume: 30 Issue: 12 DOI: 10.3788/AOS20103012.3471 Published: December 2010
Abstract:The optical joint transform correlator (JTC) is an effective technical way for image motion measurement of the space camera. Its basic principles are presented, and performance is evaluated through static simulation experiment. A calibrated image set is tested by the experimental device. The results show that, the measurement accuracy can be controlled below 0.2 pixel in two directions, which is satisfied for the space camera. The influence of centroiding window size on cross-correlation peaks locating is analyzed, based on which, intensity weighted centroiding (IWC) is proposed instead of the traditional centroiding method, by which not only the influence of centroiding window size on image motion measurement is reduced, but also the measurement accuracy is improved.
Accession Number: 20111213768121
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Record 65 of
Title:Performance of double sideband modulated probe wave in BOTDA distributed fiber sensor
Author(s):Cui, Qingsong(1,2); Pamukcu, Sibel(2); Lin, Aoxiang(3,4); Xiao, Wen(1); Toulouse, Jean(3)
Source: Microwave and Optical Technology Letters Volume: 52 Issue: 12 DOI: 10.1002/mop.25566 Published: December 2010
Abstract:We report on the performance of double sideband (DSB) modulated probe wave in Brillouin optical time domain analysis (BOTDA) distributed fiber sensor. Compared to single sideband (SSB) modulation, along the sensing fiber the pump depletion of DSB modulation is remarkably suppressed in time domain and also has a relatively narrower Brillouin gain spectrum in frequency domain. Both the theoretical simulation and the experimental results demonstrate that the DSB modulation provides potentially longer sensing distance and higher accuracy in measurement than the SSB modulation in the BOTDA distributed fiber sensor system. ? 2010 Wiley Periodicals, Inc.
Accession Number: 20114514490883
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Record 66 of
Title:Light collection systems for multiple LED arrays
Author(s):Peng, Chenhui(1); Li, Xiaoning(1); Xiong, Lingling(1); Zhang, Pu(1); Liu, Xingsheng(1,2); Wang, Jingwei(2)
Source: 2010 OSA-IEEE-COS Advances in Optoelectronics and Micro/Nano-Optics, AOM 2010 Volume: Issue: DOI: 10.1109/AOM.2010.5713510 Published: 2010
Abstract:Light emitting diode (LED) has numerous advantages such as long lifetime, large color gamut, small size and the absence of mercury vapor and thus there has been recognition that LED could be an alternative light source for projection display application. Due to its compact size, LED is a very attractive RGB light source for portable projectors. To improve the brightness of the projector, it is very critical to improve the light collection efficiency of the RGB LED light sources. In this work, traditional compound parabolic concentrator (CPC) was designed and its performance was studied. The CPC has a high collection efficiency, but its size is too bulky to be used in the portable projectors. Hence, a freeform collection system was designed and optimized to gain a compact size which can be used in the portable projectors. After optimization, it has a collection efficiency of 85%, slightly lower than that of the traditional CPC. But its diameter of the output aperture is 13.4 mm, 36% smaller than that of the traditional CPC and its length is 25 mm, 58% shorter than that of the traditional CPC. Meanwhile, the divergence angle of the freeform collection system is ±10 ° , which is smaller than that of the designed traditional CPC. Hence, the freeform collection system may be used as the collimator in the portable projection display application.
Accession Number: 20111213848030
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Record 67 of
Title:Intense green upconversion emission in Tb3+/Yb3+ codoped alumino-germano-silicate optical fibers
Author(s):Lin, Aoxiang(1,3); Liu, Xueming(1); Watekar, Pramod R.(2); Guo, Haitao(1); Peng, Bo(1); Wei, Wei(1); Lu, Min(1); Han, Won-Taek(2); Toulouse, Jean(3)
Source: Applied Optics Volume: 49 Issue: 9 DOI: 10.1364/AO.49.001671 Published: March 20, 2010
Abstract:We observed intense green upconversion emission from Tb3+ centered at 546nm due to transition 5D4 → 7F5 in Tb3+/Yb3+ codoped alumino-germano-silicate optical fibers by direct excitation of Yb3+ ions with a laser diode at 976 nm. A two-photon cooperative energy transfer upconversion among a pair of Yb3+ donor ions and a Tb3+ acceptor ion are responsible for the observed green emission. Appropriately increasing the concentration of Tb3+ relative to Yb3+ was found to facilitate the energy transfer upconversion process from Yb 3+ to Tb3+, while an excess of Tb3+ ions inversely introduced more of the concentration quenching effect and phonon-assistant backward energy transfer from Tb3+ to Yb 3+ and, therefore, damaged the observed green emission. The intensity of the observed green emission was found optimum for a concentration ratio of Tb3+ to Yb3+ of 2 : 1 in alumino-germano-silicate optical glass fibers. ? 2010 Optical Society of America.
Accession Number: 20101312803103
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Record 68 of
Title:Comprehensive performance analysis of popular odd-symmetric phase masks used for wave-front coded imaging system
Author(s):Zhao, Hui(1); Li, Yingcai(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7849 Issue: DOI: 10.1117/12.868287 Published: 2010
Abstract:Wave-front coding was proposed in 1995 and is a powerful system-level technique used to extend the depth of field (DOF) of incoherent imaging system. The key to wave-front coding lies in the design of suitable phase masks which make the imaging system insensitive to defocus and defocus-related aberrations. Among all phase masks used for wave-front coding, odd-symmetric types are dominant and can provide larger extended DOF. With the acceptable degradation of MTF (Modulation Transfer Function) taken as a criterion, optimization procedure is used to obtain the optimum parameters for popular odd-symmetric phase masks and then a comprehensive analysis is carried out by considering four factors: DOF extension capability, sensitiveness to elementary aberrations, PSF (Point Spread Function) shifting effect and restorability of intermediate blurred images. To the best of our knowledge, the comprehensive analysis on performance of popular odd-symmetric phase masks, as done in this manuscript, has not been made before. So, the work reported here could be considered as a complementary part to the field of wave-front coding. ? 2010 Copyright SPIE - The International Society for Optical Engineering.
Accession Number: 20110113551045
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Record 69 of
Title:Discriminative orthogonal neighborhood-preserving projections for classification
Author(s):Zhang, Tianhao(1); Huang, Kaiqi(2); Li, Xuelong(3); Yang, Jie(1); Tao, Dacheng(4,5,6,7)
Source: IEEE Transactions on Systems, Man, and Cybernetics, Part B: Cybernetics Volume: 40 Issue: 1 DOI: 10.1109/TSMCB.2009.2027473 Published: February 2010
Abstract:Orthogonal neighborhood-preserving projection (ONPP) is a recently developed orthogonal linear algorithm for overcoming the out-of-sample problem existing in the well-known manifold learning algorithm, i.e., locally linear embedding. It has been shown that ONPP is a strong analyzer of high-dimensional data. However, when applied to classification problems in a supervised setting, ONPP only focuses on the intraclass geometrical information while ignores the interaction of samples from different classes. To enhance the performance of ONPP in classification, a new algorithm termed discriminative ONPP (DONPP) is proposed in this paper. DONPP 1) takes into account both intraclass and interclass geometries; 2) considers the neighborhood information of interclass relationships; and 3) follows the orthogonality property of ONPP. Furthermore, DONPP is extended to the semisupervised case, i.e., semisupervised DONPP (SDONPP). This uses unlabeled samples to improve the classification accuracy of the original DONPP. Empirical studies demonstrate the effectiveness of both DONPP and SDONPP. ? 2009 IEEE.
Accession Number: 20103113113361
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Record 70 of
Title:Influence of deflector on streak tube's character
Author(s):Li, Lizhou(1); Chen, Zhengwu(1); Hu, Xin(2); Zhang, Xiaoli(1); Chen, Zhengkai(3,4); Tian, Jinshou(3); Liu, Hulin(3)
Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams Volume: 22 Issue: 6 DOI: 10.3788/HPLPB20102206.1219 Published: June 2010
Abstract:The influence of deflector position on characters of the streak tube is discussed. A large amount of electron trajectories are figured out by statistical simulation method, and the modulation transfer function(MTF) used to evaluate temporal and spatial resolution is calculated. The conclusions are as follows: the streak tube has obtained the optimal temporal resolution when the deflection plate is set to the aperture of anode, and the optimal spatial resolution is obtained when deflection plate is set to the point with minimum electron beam diameter. In addition, any perpendicular deviation of deflection plate from the axis of streak tube can worsen both temporal and spatial resolution worse, thus axis of the deflection plate should strictly overlap with the center axis of the streak tube.
Accession Number: 20102713051239
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Record 71 of
Title:The effect of the laser interference lithography patterns when substrate tilted
Author(s):Zhao, Xiaoxia(1); Wang, Hongying(1); Xie, Yongjun(2); Fan, Wenhui(2)
Source: 2010 Symposium on Photonics and Optoelectronic, SOPO 2010 - Proceedings Volume: Issue: DOI: 10.1109/SOPO.2010.5504313 Published: 2010
Abstract:The effect of the tilted substrate on the lithography patterns in maskless Laser Interference Lithography (MLIL) was numerically and experimentally studied. The experiments showed that the period of interference patterns becomes larger with increasing tilt angles of the substrate, as is in good agreement with theoretical analysis. It was also shown that there is no evident change when the rotational angle was less than 30 in our experiment. The significance of our analytical results for MLIL and the fabrication of integrated circuit was discussed. ?2010 IEEE.
Accession Number: 20103013104212
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Record 72 of
Title:Analysis of one-end-pumped Yb3+-doped gain guided and index antiguided fiber laser
Author(s):Zhou, E.(1); Zhao, B.(2); Wang, X.(3); Wang, Y.(2); Wei, W.(1,4); Peng, B.(2,4)
Source: Applied Physics B: Lasers and Optics Volume: 99 Issue: 4 DOI: 10.1007/s00340-010-3919-8 Published: June 2010
Abstract:The one-end-pumped Yb3+-doped gain guided and index antiguided (GG+IAG) fiber laser is analyzed with a rate equation model. By solving propagation rate equations, the pump and signal, the gain coefficients and other characteristics are obtained. Computation results show that a properly designed Yb3+-doped GG+IAG fiber laser can provide a large-mode laser with a short length. The most important issue addressed is the way of controlling the fiber laser length. ? Springer-Verlag 2010.
Accession Number: 20103413182086
