2014
2014
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Record 145 of
Title:Linearization of coupled pointing and tracking dynamical equations
Author(s):Luo, Cui Hua(1,2,3); Qi, Hai Feng(3); Ma, Cai Wen(3)Source: Advanced Materials Research Volume: 971-973 Issue: DOI: 10.4028/www.scientific.net/AMR.971-973.1637 Published: 2014Abstract:Cooperative pointing and tracking is one important characteristic of deep space intersatellite laser communication, so that the dynamic mathematical model is complicated nonlinearity and coupling. The contribution of this paper is to substitute the time-domain error transfer function of state equations and to linearize the state space for the sake of physical realization easily in terms of previous authors' work. The method applied is state feedback and coordinate transformation in nonlinear field, the calculated result is demonstrated that differential equations modeled can be transferred into canonical controllable form and realized physically. ? (2014) Trans Tech Publications, Switzerland.Accession Number: 20142917962090 -
Record 146 of
Title:Selective plane illumination microscopy with structured illumination based on spatial light modulators
Author(s):Li, Runze(1); Zhou, Xing(1); Wu, Di(1); Peng, Tong(1); Yang, Yanlong(1); Lei, Ming(1); Yu, Xianhua(1); Yao, Baoli(1); Ye, Tong(2)Source: Progress in Biomedical Optics and Imaging - Proceedings of SPIE Volume: 8949 Issue: DOI: 10.1117/12.2040319 Published: 2014Abstract:Structured-illumination microscopy (SIM) is an efficacious tool to decrease the contribution of the out-of-focus light to images of specimens. However, in SIM, the frequency of the spatial modulation applied to specimens should be adjustable according to the optical properties of the specimens to reach the optimal contrasts. Hence, a common theme in SIM is how the flexibility and quality of modulations at different frequencies can be improved. Digital scanned laser light-sheet microscopy with structured illumination (DSLM-SI) has been the most flexible means for generating modulation and optical sectioning. The complexity of synchronization between the temporal modulation and the beam scanning makes it hard to use and less stable; it also takes more time to acquire images for one plane than selective plane illumination microscopy (SPIM). In this report, we present a recent effort to use a spatial light modulator (SLM) to provide spatial modulation in SPIM. With the SLM, both of the frequency and phase of lateral modulation can be changed rapidly; moreover, this SLM-based SPIM can achieve fast imaging without mechanical moving parts. ? 2014 SPIE.Accession Number: 20142117732914 -
Record 147 of
Title:Preparation of the oxyfluoride glass with high 3ω laser induced damage threshold
Author(s):Hou, Chaoqi(1,2); Wang, Pengfei(1); Li, Weinan(1); Guo, Haitao(1); Fu, Lili(2); Qiao, Zebang(1); Lu, Min(1); Wei, Wei(1); Peng, Bo(1)Source: Optics and Laser Technology Volume: 56 Issue: DOI: 10.1016/j.optlastec.2013.06.015 Published: 2014Abstract:An oxyfluoride glass with good thermal stability (ΔT=313.72 C), high transmittance and excellent 3ω laser induced damage threshold (LIDT) was prepared by a high temperature melting technique. The oxyfluoride glass has an optical transmittance as high as 91.2% (without AR coatings) at 351 nm and the transmission is stable in the successive laser shots. Its 3ω LIDT is higher than that of fused silica, and the corresponding mechanism has been discussed through SEM microstructure and damage morphology observation. This novel oxyfluoride glass makes itself a promising candidate material used in 3ω high power laser system. ? 2013 Published by Elsevier Ltd.Accession Number: 20133516677748 -
Record 148 of
Title:Research of spectrum signal-to-noise ratio of large aperture static imaging spectrometer
Author(s):Wang, Shuang(1,2); Xiangli, Bin(3); Li, Li-Bo(1,2); Pi, Hai-Feng(1,2)Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 34 Issue: 3 DOI: 10.3964/j.issn.1000-0593(2014)03-0851-06 Published: March 2014Abstract:The process of acquiring hyperspectral data cube of a Large Aperture Static Imaging Spectrometer (LASIS) includes several vital and essential steps, such as interferometer modulation, rectangular convolution sampling by pixels of detector and spectra retrieving. In this process, how to precisely evaluate the Signal-Noise Ratio (SNR) of spectra and how to wholly establish a related evaluation model were both generally very complicated. After a full consideration of the transmission process, utilizing the theory of rectangular convolution sampling and the spectral retrieving method regarding the computation of real part of the discrete Fourier transform of interferogram, formulas of both spectral signal and spectral noise were deduced theoretically, and then a evaluation model regarding the spectral SNR of LASIS was established. By using this model and other design factors of LASIS involving the wavenumber related optical transmittance, the interferometer beam splitter efficiency, the detector quantum efficiency and the main circuit noise, a simulation of spectral SNR was implemented. The simulation result was compared with the measurement result of the SNR of a LASIS instrument. The SNR lines and trends of the two match each other basically in single spectral band. The average deviation between them is proved to be 3.58%. This comparison result demonstrates the feasibility and effectiveness of the evaluation model. This SNR evaluation model consisting of the main technical aspects of typical LASIS instrument from the input spectral radiation to the output spectrum data is possible to be applied widely in practical design and implement of LASIS, as well as may provide valuable reference on SNR calculation and evaluation for other imaging spectrometers.Accession Number: 20141217481911 -
Record 149 of
Title:Experimental analysis of focal fields in laser scanning fluorescence stereomicroscopy
Author(s):Yang, Yanlong(1); Peng, Tong(1); Lei, Ming(1); Li, Runze(1); Zhou, Xing(1); Wu, Di(1); Yao, Baoli(1); Ye, Tong(2)Source: Progress in Biomedical Optics and Imaging - Proceedings of SPIE Volume: 8949 Issue: DOI: 10.1117/12.2040248 Published: 2014Abstract:Bessel beams have been proved to have the ability to extend the depth of focus in fluorescence microscopy. But the depth discrimination was not investigated thoroughly. Following our previous work2, we investigated focal fields of Bessel-Gauss beams at different scanning angles. We found that the central focusing lines were tilted differently at different scanning angles. This effect manifests the ability of the true perspective view in the fluorescence stereomicroscopy. ? 2014 SPIE.Accession Number: 20142117732913 -
Record 150 of
Title:High efficient CEP-stabilized infrared optical parametric amplifier made from a BBO single crystal
Author(s):You, Lang-Fang(1,2); Ling, Wei-Jun(1,2); Li, Ke(1); Zhang, Ming-Xia(1); Zuo, Yin-Yan(1); Wang, Yi-Shan(2)Source: Wuli Xuebao/Acta Physica Sinica Volume: 63 Issue: 21 DOI: 10.7498/aps.63.214203 Published: November 5, 2014Abstract:We demonstrate an efficient tunable phase-stabilized near-infrared optical parametric amplifier (OPA) made from a BBO (β-BaB2O4) single crystal in this paper. By using the seeded white-light continuum produced by CEP(carrier envelop phase)-stabilized femtosecond laser amplifier system which is seeded into the two stages of a type II OPA system, the pump-to-signal conversion efficiency of 34% can be achieved at 1350 nm. The CEP jitter of amplified pulses measured by an f-2f interferometer is 137 mrad in 30 minutes. This paper demonstrates a simple, feasible and efficient way to produce tunable femtosecond pulses with CEP control. ? 2014 Chinese Physical Society.Accession Number: 20145200366282 -
Record 151 of
Title:Vehicle detection based on semantic component analysis
Author(s):Cui, Guosheng(1,3); Wang, Qi(2); Yuan, Yuan(1)Source: ACM International Conference Proceeding Series Volume: Issue: DOI: 10.1145/2632856.2632861 Published: 2014Abstract:Vehicle detection is a hot topic in trafic monitoring applications. Though many researchers has done a lot work towards this direction, the detection in occluded conditions is rarely explored and it still remains a challenge. In this work, we focus on the occlusion problem in vehicle detection and propose a novel method based on semantic component analysis and scale consideration. Two contributions are claimed in this procedure: 1) Tackling vehicle detection by semantic component detection and synthesis. 2) Addressing the scale variation of vehicles by simple yet effective standard component definition. The experimental results on two typical surveillance videos show that the proposed method can effectively detect the vehicles in the crowded trafic conditions with occlusion. Copyright 2014 ACM.Accession Number: 20143318062218 -
Record 152 of
Title:Anomaly detection in crowd scene via online learning
Author(s):Ma, Dandan(1,3); Wang, Qi(2); Yuan, Yuan(1)Source: ACM International Conference Proceeding Series Volume: Issue: DOI: 10.1145/2632856.2632862 Published: 2014Abstract:Anomaly detection in crowd scene has attracted an increasing attention in video surveillance, but a precise detection still remains a challenge. This paper presents a novel online learning method to automatically detect abnormal behaviors in crowd scene. Our focus is mainly on the deviation between the real motion and the predicted one. Through on-line defining experts, analyzing their motions, and dynamically updating the learned model, anomaly can be identified by the final expert joint decision. The outputs are represented as the anomaly probability of an examined frame. Compared with most of existing methods, the proposed one needs neither tracking each individual straight to the end nor requires any complex training procedure. We test the proposed method on public datasets, and the results show its effectiveness. Copyright 2014 ACM.Accession Number: 20143318062215 -
Record 153 of
Title:CFRP variable curvature mirror being capable of generating a large variation of saggitus: Prototype design and experimental demonstration
Author(s):Zhao, Hui(1); Fan, Xuewu(1); Pang, Zhihai(1); Ren, Guorui(1); Wang, Wei(1); Xie, Yongjie(1); Ma, Zhen(1); Du, Yunfei(1); Su, Yu(1); Wei, Jingxuan(2); Xie, Xiaopeng(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9272 Issue: DOI: 10.1117/12.2065554 Published: 2014Abstract:The key to realize non-moving-element optical zooming lies in VCM (variable curvature mirror). In order to obtain a large optical magnification, VCM should be capable of providing a large center deflection and this requires that the mirror material should be robust enough, require less force to deform and have a high ultimate strength. In this paper, CFRP (carbon-fiber-reinforced-polymer) is selected as the mirror material and a prototype VCM has been fabricated. With diameter of 100mm, thickness of 2mm and initial curvature radius of 1740mm, this VCM can provide a center deflection approaching nearly 23um, which proves the feasibility of CFRP in constructing VCM. Compared with the work reported in [Proc. of SPIE, 8725, 87250W, 2013], the center deflection obtained here becomes even larger. ? 2014 SPIE.Accession Number: 20150700533187 -
Record 154 of
Title:An improved opto-digital joint transform correlator reducing the influence of defocus on image motion measurement
Author(s):Zhao, Hui(1); Yi, Hongwei(1); Wei, Jingxuan(2); Xie, Xiaopeng(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9273 Issue: DOI: 10.1117/12.2064959 Published: 2014Abstract:Joint transform correlator (JTC) is a highly efficient way to measure image motion and a hybrid opto-digital JTC (HODJTC) has been proposed by us in [CHIN. OPT. LETT., Vol. 8, No. 8]. Being different from the traditional JTC, only one optical Fourier transform is needed and the optically generated joint power spectrum (JPS) is used to compute the image motion in a digital way. Although a high measurement precision can be obtained through HODJTC, the defocus will counteract the final result. In this paper, the influence of defocus is analyzed and an improved HODJTC, whose sensitiveness to defocus is reduced, is proposed. By introducing randomly generated defocus, a series of cross-correlation peak images is obtained and a subsequent spatial averaging procedure is applied to these images to generate the final cross-peak image which is used to compute the defocus invariant motion value. ? 2014 SPIE.Accession Number: 20150700527392 -
Record 155 of
Title:Investigation on wavelength multicasting technology based on XPM in a highly nonlinear fiber
Author(s):Wang, Minjie(1,2,3); Zhang, Jian-Guo(4)Source: Journal of Modern Optics Volume: 61 Issue: 13 DOI: 10.1080/09500340.2014.922631 Published: July 29, 2014Abstract:All-optical wavelength conversion with multicasting is investigated in this paper, which is based on cross-phase modulation in a highly nonlinear fiber. With a pump-modulated light and only a single continuous-wave probe, wavelength multicasting is realized by appropriately controlling the powers of two beams. Our simulation work reveals that 10 multicast channels can be obtained with their Q factors being larger than six, if both pump and probe powers are properly selected. These wavelength channels of multicasting are positioned around the central wavelength of the probe on the blue-shifted and red-shifted sides. The central wavelength and the channel spacing can be affected by the wavelengths of the probe and the pump. The wavelength multicasting technique studied in this paper is simpler and can offer more multicast channels than that based on four-wave mixing. ? 2014 Taylor & Francis.Accession Number: 20143017972323 -
Record 156 of
Title:Tunneling control of cavity linewidth narrowing via quantum interference in triangular quantum dot molecules
Author(s):Tian, Si-Cong(1); Wan, Ren-Gang(2); Xing, En-Bo(1,3); Tong, Cun-Zhu(1); Ning, Yong-Qiang(1)Source: Journal of Modern Optics Volume: 61 Issue: 18 DOI: 10.1080/09500340.2014.941431 Published: 2014Abstract:A scheme for tunneling control of cavity linewidth narrowing by quantum interference in triangular-type triple quantum dots (TQDs) is proposed. In such system, quantum interference induced by tunneling between the TQDs can result in the appearance of two transparency windows and a steep dispersion. Furthermore, when the sample is embedded in a ring cavity, an ultranarrow transmission peak is obtained within the narrowed transparency windows. And by varying the tunneling, the linewidth and the position of the ultranarrow transmission peak can be engineered. Because no coupling laser is required, the scheme proposed here is more convenient for future experiments and applications in optics, and may be useful in designing novel optoelectronic devices. ? 2014 Taylor & Francis.Accession Number: 20143600004711