2011
2011
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Record 37 of
Title:Optical data transmission at 44 terabits/s with a Kerr soliton crystal microcomb
Author(s):Tan, Mengxi(1); Corcoran, Bill(2); Xu, Xingyuan(1,2); Wu, Jiayang(1); Boes, Andreas(3); Nguyen, Thach G.(3); Chu, Sai T.(4); Little, Brent E.(5); Morandotti, Roberto(6,7); Mitchell, Arnan(3); Moss, David J.(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11713 Issue: DOI: 10.1117/12.2584014 Published: 2011Abstract:We report world record high data transmission over standard optical fiber from a single optical source. We achieve a line rate of 44.2 Terabits per second (Tb/s) employing only the C-band at 1550nm, resulting in a spectral efficiency of 10.4 bits/s/Hz. We use a new and powerful class of micro-comb called soliton crystals that exhibit robust operation and stable generation as well as a high intrinsic efficiency that, together with an extremely low spacing of 48.9 GHz enables a very high coherent data modulation format of 64 QAM. We achieve error free transmission across 75 km of standard optical fiber in the lab and over a field trial with a metropolitan optical fiber network. This work demonstrates the ability of optical micro-combs to exceed other approaches in performance for the most demanding practical optical communications applications. ? 2021 SPIE.Accession Number: 20212110379385 -
Record 38 of
Title:Thermal optimum design for tracking primary mirror of Space Telescope
Author(s):Pan, Hai-Jun(1,2); Ruan, Pinga(1); Li, Fu(1); Wang, Hong-Wei(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8196 Issue: DOI: 10.1117/12.899606 Published: 2011Abstract:In the conventional method, the structural parameters of primary mirror are usually optimized just by the requirement of mechanical performance. Because the influences of structural parameters on thermal stability are not taken fully into account in this simple method, the lightweight optimum design of primary mirror usually brings the bad thermal stability, especially in the complex environment. In order to obtain better thermal stability, a new method about structure-thermal optimum design of tracking primary mirror is discussed. During the optimum process, both the lightweight ratio and thermal stability will be taken into account. The structure-thermal optimum is introduced into the analysis process and commenced after lightweight design as the secondary optimum. Using the engineering analysis of software ANSYS, a parameter finite element analysis (FEA) model of mirror is built. On the premise of appropriate lightweight ratio, the RMS of structure-thermal deformation of mirror surface and lightweight ratio are assigned to be state variables, and the maximal RMS of temperature gradient load to be object variable. The results show that certain structural parameters of tracking primary mirror have different influences on mechanical performance and thermal stability, even they are opposite. By structure-thermal optimizing, the optimized mirror model discussed in this paper has better thermal stability than the old one under the same thermal loads, which can drastically reduce difficulty in thermal control. ? 2011 SPIE.Accession Number: 20113614296260 -
Record 39 of
Title:Technology research of high-definition CCD camera based on FPGA
Author(s):Tian, Yan(1); Cao, Jian-Zhong(1); Yao, Da-Wei(1); Xu, Zhao-Hui(1); Huang, Jing(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8194 Issue: DOI: 10.1117/12.900523 Published: 2011Abstract:This paper researches the digital high definition imaging technology and successfully designs a digital high definition camera system. The system takes large array CCD(KAI-2093CM) which conforms to SMEPT 274M standard as photoelectric transfer device, FPGA+AFE as framework, HD-SDI as transforming interface, and combines with the current advanced digital high definition video standard. The result of imaging shows that the high definition camera can realize high definition shooting. The pictures are clear and can be displayed with no stagnation in real time. Moreover, the small camera with high resolution can be applied for high definition shooting in aerospace and other fields. ? 2011 SPIE.Accession Number: 20113714325927 -
Record 40 of
Title:Growth of short-period InAs/GaSb superlattices for infrared sensing
Author(s):Wang, Tao(1); Yang, Jin(1,3); Yin, Fei(1); Wang, Jing-Wei(1); Hu, Ya-Nan(1,3); Zhang, Li-Chen(1,3); Yin, Jing-Zhi(2)Source: Hongwai Yu Haomibo Xuebao/Journal of Infrared and Millimeter Waves Volume: 30 Issue: 6 DOI: 10.3724/sp.j.1010.2011.00511 Published: December 2011Abstract:The InAs/GaSb superlattice were prepared by metal organic chemical vapor deposition (MOCVD) on GaSb substrate. The optimized thickness and the various growth parameters were explored as well as the importance of source flux control. The photoluminescence (PL) spectra, x-ray diffraction data (XRD) and the surface topography map showed that the superlattice can response to incident light with long wavelength of 10 μm, and has good surface morphology and epitaxial layer quality.Accession Number: 20120114659116 -
Record 41 of
Title:Putting poses on manifold for action recognition
Author(s):Cao, Xianbin(1,2); Ning, Bo(1); Yan, Pingkun(3); Li, Xuelong(3)Source: IEEE International Workshop on Machine Learning for Signal Processing Volume: Issue: DOI: 10.1109/MLSP.2011.6064580 Published: 2011Abstract:In action recognition, bag of words based approaches have been shown to be successful, for which the quality of codebook is critical. This paper proposes a novel approach to select key poses for the codebook, which models the descriptor space utilizing manifold learning to recover the geometric structure of the descriptors on a lower dimensional manifold space. A PageRank based centrality measure is developed to select key poses on the manifold. In each step, a key pose is selected and the remaining model is modified to maximize the discriminative power of selected codebook. In classification, the ambiguity of each action couple is evaluated through cross validation. An additional subdivision will be executed for ambiguous pairs. Experiments on ut-tower dataset showed that our method is able to obtain better performance than the state-of-the-art methods. ? 2011 IEEE.Accession Number: 20114914573651 -
Record 42 of
Title:Overall scheme and on-orbit images of Chang'E-2 lunar satellite CCD stereo camera
Author(s):Zhao, Baochang(1,4); Yang, Jianfeng(1,2,4); Wen, Desheng(1,2); Gao, Wei(1,4); Chang, Lingying(1,3); Song, Zongxi(1); Xue, Bin(1,2,4); Zhao, Wei(1,4)Source: Science China Technological Sciences Volume: 54 Issue: 9 DOI: 10.1007/s11431-011-4519-5 Published: September 2011Abstract:The goals of engineering and scientific missions for Chang'E-2 lunar satellite require high detection sensitivity and large imaging dynamic range for the onboard CCD cameras. The TDI CCD image sensor was adopted for the two linear CCD stereo cameras for the first time in the lunar reconnaissance of the world. The design argumentation is described in this paper. The analysis shows that the imagers meet the mission requirements. The satellite was launched on 1 October 2010 at zero window. The cameras obtained images of 7 m resolution on the 100 km orbit for the first time on 24 October 2010, and operated once again on 27 October 2010 to take stereo images of the Sinus Iridum with the resolution better than 1.5 m. On the near-moon-arc of 15 km×100 km elliptical orbit, the images are very clear and rich of grey scales, indicating successful completion of the Chang'E-2 engineering mission. At the present the cameras are acquiring the full lunar surface stereo images with 7 m resolution on the 100 km circular orbit to complete their scientific mission. ? 2011 Science China Press and Springer-Verlag Berlin Heidelberg.Accession Number: 20113314245072 -
Record 43 of
Title:Investigation of energy transfer and upconversion luminescence in Er3+/Ho3+-codoped GeS2-In2S3-CsI glasses
Author(s):Deng, Sheng-Wei(1); Xu, Tie-Feng(1); Dai, Shi-Xun(1,2); Wang, Xun-Si(1); Nie, Qiu-Hua(1); Shen, Xiang(1); Zhang, Xiang-Hua(1,3)Source: Gongneng Cailiao/Journal of Functional Materials Volume: 42 Issue: 2 DOI: Published: February 2011Abstract:A serials of chalcohalide glasses based on the composition 80GeS2-10In2S3-10CsI doped with the different Er3+/Ho3+ ions ratio were synthesized by melt-quenching technique. The state stability, Raman spectra, absorption spectra, upconversion emission spectra of glass samples were measured. Three intense upconversion luminescence emissions are observed at around 526, 549, and 660 nm, which correspond to Er3+:2H11/2 &rarr4I15/2, Er3+:4S3/2 &rarr4I15/2 +Ho3+:5S2 (5F4)&rarr5I8, and Er3+:4F9/2 &rarr4I15/2 + Ho3+:5F5 &rarr5I8 transitions, respectively. In 0.6mol% Er2S3/xHo2S3 codoped glasses, increase of Ho2S3 had positive effect up to the upconversion fluorescences. The upconversion emissions reach the maximum values when Ho2S3 is 0.6 mol%, and the intensities of the green and red light emissions were 4.2 and 10 times stronger than those un-doped Ho2S3, respectively. The possibie upconversion mechanisms and energy transfer between Er3+ and Ho3+ were also estimated and evaluated. All the three emissions are based on two photon absorption processes.Accession Number: 20111513904800 -
Record 44 of
Title:Parallel two-step phase-shifting digital holograph microscopy based on a grating pair
Author(s):Gao, Peng(1,3); Yao, Baoli(1); Harder, Irina(2); Min, Junwei(1); Guo, Rongli(1); Zheng, Juanjuan(1); Ye, Tong(1)Source: Journal of the Optical Society of America A: Optics and Image Science, and Vision Volume: 28 Issue: 3 DOI: 10.1364/JOSAA.28.000434 Published: March 2011Abstract:An optical configuration for parallel two-step phase-shifting digital holographic microscopy (DHM) based on a grating pair is proposed for the purpose of real-time phase microscopy. Orthogonally circularly polarized object and reference waves are diffracted twice by a pair of gratings, and two parallel copies for each beams come into being. Combined with polarization elements, parallel two-step phase-shifting holograms are obtained. Based on the proposed configuration, two schemes of DHM, i.e., slightly off-axis and on-axis DHM, have been implemented. The slightly off-axis DHM suppresses the dc term by subtracting the two phase-shifting holograms from each other, thus the requirement on the off-axis angle and sampling power of the CCD camera is reduced greatly. The on-axis DHM has the least requirement on the resolving power of the CCD camera, while it requires that the reference wave is premeasured and its intensity is no less than 2 times the maximal intensity of the object wave. ? 2011 Optical Society of America.Accession Number: 20111013735296 -
Record 45 of
Title:Nonequilibrium plasmas generated by dielectric barrier discharges at atmospheric pressure
Author(s):Tang, Jie(1); Zhao, Wei(1); Duan, Jiana(2); Duan, Yixiang(1,3)Source: IEEE Transactions on Plasma Science Volume: 39 Issue: 11 PART 1 DOI: 10.1109/TPS.2011.2159126 Published: November 2011Abstract:Both propane plasma and air plasma are successfully generated at atmospheric pressure by using two dielectric barrier discharge reactors with different configurations, in which one is used to activate propane and the other is used to activate air. The plasma pictures show that the microdischarge channels in the plasmas increase and become increasingly more uniform with the deposited power under both activation methods. It is found that the propane plasma is of an ivory white color, while the air plasma is purple, as a result of the different gas components. A 30-W propane or air plasma leads to a significant temperature rise of the main flame, attributed to the production of reactive radicals and fuel fragments in such plasmas. ? 2006 IEEE.Accession Number: 20114714532615 -
Record 46 of
Title:Enhancement of nonreciprocal phase shift by magneto-optical slot waveguide with a compensation wall
Author(s):Zhang, Wenfu(1,2); Mu, Jian-Wei(3); Huang, Wei-Ping(3); Zhao, Wei(1)Source: Applied Physics Letters Volume: 98 Issue: 17 DOI: 10.1063/1.3584035 Published: April 25, 2011Abstract:We demonstrated that the nonreciprocal phase shift (NPS) can be efficiently enhanced by introducing a low-index magneto-optical (MO) slot with a compensation wall (CW) in a high-index non-MO waveguide. The proposed structure has been examined by a perturbation theory and it is found that by adjusting the slot width and waveguide height, more than 20 times enhancement of NPS comparing with the rib waveguide with a CW can be realized. ? 2011 American Institute of Physics.Accession Number: 20111913967412 -
Record 47 of
Title:Rapid pedestrian detection in unseen scenes
Author(s):Cao, Xianbin(1,3); Wang, Zhong(1); Yan, Pingkun(2); Li, Xuelong(2)Source: Neurocomputing Volume: 74 Issue: 17 DOI: 10.1016/j.neucom.2011.05.019 Published: October 2011Abstract:In this paper, a rapid adaptive pedestrian detection method based on cascade classifier with ternary pattern is proposed. The proposed method achieves its goal by employing the following three new strategies: (1) A method for adjusting the key parameters of the trained cascade classifier dynamically for detecting pedestrians in unseen scenes using only a small amount of labeled data from the new scenes. (2) An efficient optimization method is proposed, based on the cross entropy method and a priori knowledge of the scenes, to solve the classifier parameter optimization problem. (3) In order to further speed up pedestrian detection in unseen scenes, each strong classifier in the cascade employs a ternary detection pattern. In our experiments, two significantly different datasets, AHHF and NICTA, were used as the training set and testing set, respectively. The experimental results showed that the proposed method can quickly adapt a previously trained detector for pedestrian detection in various scenes compared with other existing methods. ? 2011 Elsevier B.V.Accession Number: 20113814357633 -
Record 48 of
Title:Wideband ultraflat slow light with large group index in a W1 photonic crystal waveguide
Author(s):Liang, Jian(1,2); Ren, Li-Yong(1); Yun, Mao-Jin(2); Han, Xu(1); Wang, Xing-Jun(3)Source: Journal of Applied Physics Volume: 110 Issue: 6 DOI: 10.1063/1.3634074 Published: September 15, 2011Abstract:We demonstrate that slow light with large group-index, wideband, and low dispersion can be realized in a silicon-on-insulator W1-type photonic crystal waveguide by simply shifting the first two rows of air-holes adjacent to the waveguide to specific directions. Keeping the group index at 46, 60, 86, 111, 151, and 233, respectively, while restricting its variation within a 10 range, we accordingly obtain a slow light bandwidth of 9.0 nm, 6.7 nm, 4.6 nm, 3.3 nm, 2.4 nm, and 1.7 nm, respectively. The normalized delay-bandwidth product keeps around 0.25 for all cases. Moreover, we obtain ultraflat slow light with bandwidths over 3.0 nm, 2.4 nm, 1.6 nm, 1.3 nm, 0.93 nm, and 0.6 nm, respectively, where the group index variation is in a range of only 0.8. Numerical simulations are performed, utilizing the 2D plane wave expansion method and the finite-difference time-domain method. ? 2011 American Institute of Physics.Accession Number: 20114114412956