2015
2015
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Record 313 of
Title:Four-phase closure algorithm for coherent field imaging
Author(s):Cao, Bei(1); Luo, Xiu-Juan(1); Si, Qing-Dan(1); Zeng, Zhi-Hong(1)Source: Wuli Xuebao/Acta Physica Sinica Volume: 64 Issue: 5 DOI: 10.7498/aps.64.054204 Published: March 5, 2015Abstract:According to the realization principle of phase closure in coherent field imaging, a new four-phase closure (FPC) algorithm is proposed for T-array multi-beam transmitter system. A type of four-item measurement radio of closure phase is first defined, and then the validity of FPC is confirmed in cancelling out the random atmospheric phase aberrations as well as eliminating atmospheric scintillation effect on degradation of the reconstructed image. Simulations prove the effectiveness of FPC, providing a new approach in removing atmospheric aberrations for multi-beam coherence field imaging. ?, 2015, Institute of Physics, Chinese Academy of Sciences. All right reserved.Accession Number: 20151100627711 -
Record 314 of
Title:Impact of evolving surface nanoscale topologies in femtosecond laser structuring of Ni-based superalloy CMSX-4
Author(s):Li, Chen(1,2,3); Cheng, Guang-Hua(1); Colombier, Jean-Philippe(2); Faure, Nicolas(2); Reynaud, Stéphanie(2); Zhang, Hao(2); Jamon, Damien(2); Stoian, Razvan(2)Source: Journal of Optics (United Kingdom) Volume: 18 Issue: 1 DOI: 10.1088/2040-8978/18/1/015402 Published: November 30, 2015Abstract:We investigate the role of surface nanoscale topographies in the inhomogeneous coupling of laser radiation to Ni-based superalloy CMSX-4 surfaces and in the formation of laser-induced periodic surface structures. The initial surface arbitrary roughness is already able, upon laser exposure, to induce low-spatial-frequency and high-spatial-frequency structures, actively determining an interference of incoming and scattered fields resulting in spatial energy modulation. A topology variation with the incoming dose via the number of pulses determines a correlated evolution in the regular ripple arrangements. The scattering pattern is severely influenced by the scattering source geometries. Therefore, we equally study experimentally the role of one-dimensional nanoscale grooves in determining polarization-dependent structuring patterns at increasing irradiation dose. Finally, the role of surface nanostructures in generating the surface modulation of deposited energy is analyzed by finite-difference-time-domain simulation. Ripple formation in multi-pulses is a result of the feedback process between light and nanostructures. ? 2016 IOP Publishing Ltd.Accession Number: 20155201733958 -
Record 315 of
Title:Low-power-threshold photonic saturable absorber in nonlinear chalcogenide glass
Author(s):Minardi, S.(1); Cheng, G.(2,3); D'Amico, C.(2); Stoian, R.(2)Source: Optics Letters Volume: 40 Issue: 2 DOI: 10.1364/OL.40.000257 Published: January 15, 2015Abstract:We experimentally demonstrate controllable nonlinear modulation of optical guiding in ultrafast laser-written evanescently coupled waveguide arrays in bulk gallium lanthanum sulfide chalcogenide glass. The intensity-dependent response is validated by simulating light propagation in waveguide arrays with instantaneous Kerr nonlinearity using a discrete-continuous spatiotemporal unidirectional Maxwell equation model. The intensity-driven modulation of transmission in multicore structures acts as a potential saturable absorber at kilowatt threshold levels. ? 2015 Optical Society of America.Accession Number: 20151100620608 -
Record 316 of
Title:Precision conveyance of microwave photon transmit electricity
Author(s):Chen, Ding-Yue(1); Zhang, Yong-Hui(2); Zhou, Ren-Kui(3); Yang, Li(1); Gong, Yong-Yu(1); Yin, Lian-Jie(1); Zhao, Chen-Chuang(1)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 23 Issue: DOI: 10.3788/OPE.20152313.0209 Published: October 1, 2015Abstract:A precision conveyance of microwave photon transmit electricity was researched. The principle of microwave photo transmit electricity and its advantages were introduced. Then, a element configuration and mathematical algorithm models of energy conversion based on the system of remote microwave photon transmit electricity were established. The energy conversion relationships between the blast-off carry and the take-over carry in microwave photon transmit electricity were analyzed. The power SOC (State of Charge) of precision conveyance was researched under ADVISOR software, and power capability was tested on the system of microwave photon transmit electricity. Experimental results show that the system of microwave photon transmit electricity designed and parameter matching are relatively rational, thus the efficient operation of precision conveyance of the purely dynamoelectric type has been achieved. The research helps to enrich and develop the science of microwave photon transmit electricity, and plays an important role in the research and development for new energy precision conveyances. ? 2015, Chinese Academy of Sciences. All right reserved.Accession Number: 20155201713582 -
Record 317 of
Title:Mining Spatialoral Patterns and Structural Sparsity for Human Motion Data Denoising
Author(s):Feng, Yinfu(1); Ji, Mingming(1); Xiao, Jun(1); Yang, Xiaosong(2); Zhang, Jian J.(2); Zhuang, Yueting(1); Li, Xuelong(3)Source: IEEE Transactions on Cybernetics Volume: 45 Issue: 12 DOI: 10.1109/TCYB.2014.2381659 Published: December 2015Abstract:Motion capture is an important technique with a wide range of applications in areas such as computer vision, computer animation, film production, and medical rehabilitation. Even with the professional motion capture systems, the acquired raw data mostly contain inevitable noises and outliers. To denoise the data, numerous methods have been developed, while this problem still remains a challenge due to the high complexity of human motion and the diversity of real-life situations. In this paper, we propose a data-driven-based robust human motion denoising approach by mining the spatialoral patterns and the structural sparsity embedded in motion data. We first replace the regularly used entire pose model with a much fine-grained partlet model as feature representation to exploit the abundant local body part posture and movement similarities. Then, a robust dictionary learning algorithm is proposed to learn multiple compact and representative motion dictionaries from the training data in parallel. Finally, we reformulate the human motion denoising problem as a robust structured sparse coding problem in which both the noise distribution information and the temporal smoothness property of human motion have been jointly taken into account. Compared with several state-of-the-art motion denoising methods on both the synthetic and real noisy motion data, our method consistently yields better performance than its counterparts. The outputs of our approach are much more stable than that of the others. In addition, it is much easier to setup the training dataset of our method than that of the other data-driven-based methods. ? 2013 IEEE.Accession Number: 20150200417406 -
Record 318 of
Title:Tubular depressed cladding waveguide laser realized in Yb: YAG by direct inscription of femtosecond laser
Author(s):Tang, Wenlong(1,2); Zhang, Wenfu(1); Liu, Xin(1,2); Liu, Shuang(1,2); Stoian, Razvan(3); Cheng, Guanghua(1)Source: Journal of Optics (United Kingdom) Volume: 17 Issue: 10 DOI: 10.1088/2040-8978/17/10/105803 Published: September 4, 2015Abstract:We report on the fabrication of tubular depressed cladding waveguides in single crystalline Yb:YAG by the direct femtosecond laser writing technique. Full control over the confined light spatial distribution is demonstrated by the photoinscription of high index contrast waveguides with tubular configuration. Under optical pumping, highly efficient laser oscillation in depressed cladding waveguide at 1030 nm is demonstrated. The maximum output power obtained is 68 mW with a slope efficiency of 35% for an outcoupling transmission of 50%. A slope efficiency as high as 44% is realized when the coupling output ratio is 91% and a low lasing threshold of 70 mW is achieved with the output coupling mirror of 10%. ? 2015 IOP Publishing Ltd.Accession Number: 20154701600843 -
Record 319 of
Title:Automatic segmentation of breast lesions for interaction in ultrasonic computer-aided diagnosis
Author(s):Huang, Qinghua(1); Yang, Feibin(1); Liu, Longzhong(2); Li, Xuelong(3)Source: Information Sciences Volume: 314 Issue: DOI: 10.1016/j.ins.2014.08.021 Published: September 1, 2015Abstract:Breast cancer is one of the most commonly diagnosed cancer types among women. Sonography has been regarded as an important imaging modality for diagnosis of breast lesions. Due to the speckle and the variance in shape and appearance of sonographic lesions, fully automatic segmentation of the breast tumor regions still remains a challenging task. In this paper, we propose an automatic interaction scheme based on an object recognition method to segment the lesions in breast ultrasound images. In this scheme, a 2D ultrasound image is firstly filtered with a total-variation model to reduce the speckle noise. A robust graph-based segmentation method is then used to segment the image into a number of sub-regions. An object recognition method incorporating the procedures of image feature extraction, feature selection and classification is proposed to automatically identify the regions which are associated with breast tumors. Finally, an active contour model is used to refine the contours of the regions that are recognized as tumors. This scheme is validated on a database of 46 breast ultrasound images with diagnosed tumors. The experimental results show that our scheme can segment the breast ultrasound images automatically, indicating its good performance in real applications. ? 2014 Elsevier Inc. All rights reserved.Accession Number: 20152000847969 -
Record 320 of
Title:Yb-doped large-mode-area laser fiber fabricated by halide-gas-phase-doping technique
Author(s):Peng, Kun(1,2,3); Wang, Yuying(1); Ni, Li(1); Wang, Zhen(1,2,3); Gao, Cong(1); Zhan, Huan(2,3); Wang, Jianjun(1); Jing, Feng(1); Lin, Aoxiang(1)Source: Laser Physics Volume: 25 Issue: 6 DOI: 10.1088/1054-660X/25/6/065801 Published: June 1, 2015Abstract:In this manuscript, we designed a rare-earth-halide gas-phase-doping setup to fabricate a large-mode-area fiber for high power laser applications. YbCl3 and AlCl3 halides are evaporated, carried respectively and finally mixed with usual host gas material SiCl4 at the hot zone of MCVD system. Owing to the all-gas-phasing reaction process and environment, the home-made Yb-doped fiber preform has a homogeneous large core and modulated refractive index profile to keep high beam quality. The drawn fiber core has a small numerical aperture of 0.07 and high Yb concentration of 9500 ppm. By using a master oscillator power amplifier system, nearly kW-level (951 W) laser output power was obtained with a slope efficiency of 83.3% at 1063.8 nm, indicating the competition and potential of the halide-gas-phase-doping technique for high power laser fiber fabrication. ? 2015 Astro Ltd.Accession Number: 20152200883736 -
Record 321 of
Title:Yb-doped passively mode-locked fiber laser with Bi2Te3-deposited
Author(s):Li, Lu(1,3,4); Yan, Pei-Guang(2); Wang, Yong-Gang(1); Duan, Li-Na(1,4); Sun, Hang(1); Si, Jin-Hai(3)Source: Chinese Physics B Volume: 24 Issue: 12 DOI: 10.1088/1674-1056/24/12/124204 Published: October 20, 2015Abstract:In this study we present an all-normal-dispersion Yb-doped fiber laser passively mode-locked with topological insulator (Bi2Te3) saturable absorber. The saturable absorber device is fabricated by depositing Bi2Te3 on a tapered fiber through using pulsed laser deposition (PLD) technology, which can give rise to less non-saturable losses than most of the solution processing methods. Owing to the long interaction length, Bi2Te3 is not exposed to high optical power, which allows the saturable absorber device to work in a high power regime. The modulation depth of this kind of saturable absorber is measured to be 10%. By combining the saturable absorber device with Yb-doped fiber laser, a mode-locked pulse operating at a repetition rate of 19.8 MHz is achieved. The 3-dB spectral width and pulse duration are measured to be 1.245 nm and 317 ps, respectively. ? 2015 Chinese Physical Society and IOP Publishing Ltd.Accession Number: 20155101678612 -
Record 322 of
Title:Yb-doped LMA fiber fabrication using chelate precursor doping technique
Author(s):Wang, Zhen(1,2,3); Gao, Cong(1); Ni, Li(1); Wang, Xiaolong(1); Peng, Kun(1,2,3); Wang, Yuying(1); Zhan, Huan(2,3); Wang, Jianjun(1); Jing, Feng(1); Lin, Aoxiang(1)Source: 2015 11th Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2015 Volume: 1 Issue: DOI: 10.1109/CLEOPR.2015.7375814 Published: January 7, 2016Abstract:We report on the fabrication of a kW-level Yb-doped fiber by using chelate precursor doping technique. Lasing performance was tested up to 1 kW laser output with slope efficiency of 81.8%. ? 2015 IEEE.Accession Number: 20161602246685 -
Record 323 of
Title:A new surface temperature measurement using infrared detector
Author(s):Xie, Qingsheng(1); Liu, Wei(1); Leng, Hanbing(1); Yi, Bo(1); Wang, Zefeng(1); Chen, Yaohong(1); Duan, Chengpeng(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9449 Issue: DOI: 10.1117/12.2075552 Published: 2015Abstract:This paper describe a research theoretically of the conversion result to the surface temperature based on long wave infrared detector, proposed a temperature measurement, then validate it by experiments. First, it introduces the constitution and measurement principle of the medical infrared thermal imager. Then, the conversion drift characteristic of infrared detect is described, the experimental data under variable environment is analyzed, and a temperature measurement and a drift compensation formula is proposed. Finally, some experiment with black body was accomplished. The results show the temperature error is under 0.3°C, confirm the validity of the measurement. ? 2015 SPIE.Accession Number: 20151100635591 -
Record 324 of
Title:Study on properties of speckle field formed by Laguerre-Gaussian beam illumination
Author(s):Li, Xinzhong(1,2); Tian, Xiaomin(1); Wang, Hui(1); Tang, Jie(2); Wang, Yishan(2); Nie, Zhaogang(3); Li, Hehe(1); Wang, Jingge(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 35 Issue: 7 DOI: 10.3788/AOS201535.0726001 Published: July 10, 2015Abstract:The properties of speckle field is studied when Laguerre-Gaussian (LG) beams illuminate a ground glass plate. The LG vortex beams are generated by a spatial light modulator combing with computer-generated hologram. The relation of speckle size and azimuthal and radial indices and the bright region of the LG beams are analyzed experimentally. Experimental results show that the speckle size decreases linearly with the azimuthal index increasing for certain radial index. Similarly, the speckle size also decreases with the radial index increasing for certain azimuthal index. Moreover, the speckle size is proportional to the negative factor of illuminating area of the LG beam. Further, the negative factor is gradual close to the results of Gaussian beam illuminating with the increasing radial index. ?, 2015, Chinese Optical Society. All right reserved.Accession Number: 20153601250796