-
Record 193 of
Title:Ultrafast optical beam deflection in a pump probe configuration
Author(s):Liang, Lingliang(1,2,3); Tian, Jinshou(1); Wang, Tao(1); Wu, Shengli(3); Li, Fuli(3); Wang, Junfeng(1); Gao, Guilong(1,2,3)
Source: Chinese Physics B Volume: 25 Issue: 9 DOI: 10.1088/1674-1056/25/9/090602 Published: September 2016
Abstract:Propagation of a signal beam in an AlGaAs/GaAs waveguide multiple-prism light deflector is theoretically investigated by solving the scalar Helmholtz equation to obtain the dependences of the temporal and spatial resolvable characteristics of the ultrafast deflector on the material dispersion of GaAs including group velocity dispersion and angular dispersion, interface reflection, and interface scattering of multiple-prism deflector. Furthermore, we experimentally confirm that, in this ultrafast beam deflection device, the deflecting angle of the signal light beam is linear with the pump fluence and the temporal resolution of the ultrafast deflection is 10 ps. Our results show that the improvement of the temporal and spatial resolvable performances is possible by properly choosing the structural parameters and enhancing the quality of the device. ? 2016 Chinese Physical Society and IOP Publishing Ltd.
Accession Number: 20163902841036
-
Record 194 of
Title:Slow axis collimation lens with variable curvature radius for semiconductor laser bars
Author(s):Xiong, Ling-Ling(1); Cai, Lei(2); Zheng, Yan-Fang(1); Liu, Hui(1,2); Zhang, Pu(1); Nie, Zhi-Qiang(1); Liu, Xing-Sheng(1,2)
Source: Optics and Laser Technology Volume: 77 Issue: DOI: 10.1016/j.optlastec.2015.08.004 Published: March 1, 2016
Abstract:Based on Snell's law and the constant phase in the front of optical field, a design method of the slow axis collimation lens with variable curvature radius is proposed for semiconductor laser bars. Variable radius of the collimator is designed by the transmission angle, and it is demonstrated that the collimator has good beam collimation ability by material with low refractive index. Resorting to the design thought of finite element method, the surface of the collimator has been divided, and it is feasible to be fabricated. This method is applied as an example in collimation of a 976 nm semiconductor laser bar. 6 mrad divergence angle of collimated beam at slow axis is realized by the designed collimation lens with refraction index of 1.51. ? 2015 Published by Elsevier Ltd.
Accession Number: 20153601228786
-
Record 195 of
Title:Reflectivity and depth images based on time-correlated single photon counting technique
Author(s):Duan, Xuejie(1); Ma, Lin(1); Kang, Yan(2); Zhang, Tongyi(2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10155 Issue: DOI: 10.1117/12.2247242 Published: 2016
Abstract:We presented three-dimensional image including reflectivity and depth image of a target with two traditional optical imaging systems based on time-correlated single photon counting technique (TCSPC), when it was illuminated by a MHz repetition rate pulsed laser source. The first one is bi-static system of which transmitted and received beams path are separated. Another one called mono-static system of which transmit and receive channels are coaxial, so it was also named by transceiver system. Experimental results produced by both systems showed that the mono-static system had more advantages of less noise from ambient light and no limitation about field area of view. While in practical applications, the target was far away leading to there were few photons return which was prejudicial to build 3D images with traditional imaging system. Thus an advanced one named first photon system was presented. This one was also a mono-static system on hardware system structure, but the control system structure was different with traditional transceiver system described in this paper. The difference was that the first return photon per pixel was recorded across system with first photon system, instead of overall return photons per pixel. That's to say only one detected return photon is needed for per pixel of this system to rebuild 3D images of target with less energy and time. ? 2016 SPIE.
Accession Number: 20170103223560
-
Record 196 of
Title:Slow light and fast light in microfiber double-knot resonator with a parallel structure
Author(s):Xu, Yiping(1); Ren, Liyong(2); Ma, Chengju(3); Kong, Xudong(2); Ren, Kaili(2)
Source: Applied Optics Volume: 55 Issue: 30 DOI: 10.1364/AO.55.008612 Published: October 20, 2016
Abstract:Based on the theoretical model of a microfiber double-knot resonator with a parallel structure, numerical simulations on the transmission spectrum, the phase, and the group time delay of the resonator as a function of wavelengths are given. We find that with this kind of resonator both slow light and fast light can be obtained at different resonant wavelengths. Experimentally, such a kind of microfiber resonator was fabricated successfully. The transmission spectrum of the fabricated resonator is well consistent with the theoretical simulation. A slow-light delay of about 38 ps and a fast-light advance of about 40 ps are demonstrated at different wavelengths, which might benefit the resonator to the applications in data delay lines, optical buffers, and optical memories. ? 2016 Optical Society of America.
Accession Number: 20164302952756
-
Record 197 of
Title:126 W fiber laser at 1018 nm and its application in tandem pumped fiber amplifier
Author(s):Yang, Hening(1,2,3); Zhao, Wei(1); Si, Jinhai(2); Zhao, Baoyin(1); Zhu, Yonggang(1)
Source: Journal of Optics (United Kingdom) Volume: 18 Issue: 12 DOI: 10.1088/2040-8978/18/12/125801 Published: December 2016
Abstract:We report on a 126 W fiber laser operating at 1018 nm with an optical efficiency of 75%. The optimal length for such a fiber laser is theoretically analyzed using steady-state rate equations including amplified spontaneous emission. Excellent agreement on the maximum output power is achieved between the numerical result and the experimental counterpart. Furthermore, a monolithic tandem pumped fiber amplifier is established by using conventional 30/250 μm double clad ytterbium-doped fiber, and 185 W output power with 85% optical efficiency is realized. ? 2016 IOP Publishing Ltd.
Accession Number: 20170403277459
-
Record 198 of
Title:Gird-control electron gun with multiple focusing electrode
Author(s):Qiang, Peng-Fei(1); Li, Lin-Sen(1,2); Liu, Duo(1,2); Liu, Yong-An(1); Sheng, Li-Zhi(1); Zhao, Bao-Sheng(1)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 45 Issue: 4 DOI: 10.3788/gzxb20164504.0423005 Published: April 1, 2016
Abstract:An electron gun with multiple focus system was designed, and a smaller beam spot was obtained in the computer simulation technology. The different cathode emission models would be actived when different voltage was load on the gird electrode, and which affects the number of electrons emitted from cathode significantly, the number of electrons would increase and decrease under the Schottky emission and Rejecting-field emission mode. When voltage of focusing electrodes is U1:U2:U3:U4:U5=5:8:15:70:100, the spot size of 160 mm at the distance of 10 m was acquired in the electron gun model. ? 2016, Chinese Optical Society. All right reserved.
Accession Number: 20161902355973
-
Record 199 of
Title:Spatiotemporal Statistics for Video Quality Assessment
Author(s):Li, Xuelong(1); Guo, Qun(1); Lu, Xiaoqiang(1)
Source: IEEE Transactions on Image Processing Volume: 25 Issue: 7 DOI: 10.1109/TIP.2016.2568752 Published: July 2016
Abstract:It is an important task to design models for universal no-reference video quality assessment (NR-VQA) in multiple video processing and computer vision applications. However, most existing NR-VQA metrics are designed for specific distortion types, which are not often aware in practical applications. A further deficiency is that the spatial and temporal information of videos is hardly considered simultaneously. In this paper, we propose a new NR-VQA metric based on the spatiotemporal natural video statistics in 3D discrete cosine transform (3D-DCT) domain. In the proposed method, a set of features are first extracted based on the statistical analysis of 3D-DCT coefficients to characterize the spatiotemporal statistics of videos in different views. These features are used to predict the perceived video quality via the efficient linear support vector regression model afterward. The contributions of this paper are: 1) we explore the spatiotemporal statistics of videos in the 3D-DCT domain that has the inherent spatiotemporal encoding advantage over other widely used 2D transformations; 2) we extract a small set of simple but effective statistical features for video visual quality prediction; and 3) the proposed method is universal for multiple types of distortions and robust to different databases. The proposed method is tested on four widely used video databases. Extensive experimental results demonstrate that the proposed method is competitive with the state-of-Art NR-VQA metrics and the top-performing full-reference VQA and reduced-reference VQA metrics. ? 1992-2012 IEEE.
Accession Number: 20162502512485
-
Record 200 of
Title:Packaging of hard solder 500W QCW diode laser array
Author(s):Li, Xiaoning(1); Wang, Jingwei(1); Hou, Dong(1); Nie, Zhiqiang(2); Liu, Xingsheng(1,2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9730 Issue: DOI: 10.1117/12.2213977 Published: June 30, 2016
Abstract:The package structure critically influences the major characteristics of diode laser, such as thermal behavior, output power, wavelength and smile effect. In this work, a novel micro channel cooler (MCC) for stack array laser with good heat dissipation capability and high reliability is presented. Numerical simulations of thermal management with different MCC structure are conducted and analyzed. Based on this new MCC packaging structure, a series of QCW 500W high power laser arrays with hard solder packaging technology has been fabricated. The performances of the laser arrays are characterized. A narrow spectrum of 3.12 nm and an excellent smile value are obtained. The lifetime of the laser array is more than 1.38×109 shots and still ongoing. ? 2016 SPIE.
Accession Number: 20163002634471
-
Record 201 of
Title:Stable all-fiber Er-doped Q-switched laser with a WS2/fluorine mica (FM) saturable absorber
Author(s):Li, Lu(1,2); Wang, Zhenfu(2); Wang, Yonggang(2); Wang, Xi(2); Yang, Guowen(2); Jiang, Shouzhen(3)
Source: Laser Physics Volume: 26 Issue: 10 DOI: 10.1088/1054-660X/26/10/105101 Published: October 2016
Abstract:This paper presents a stable all-fiber Q-switched Er-doped fiber (EDF) laser with WS2/fluorine mica (FM) as the saturable absorber (SA). The SA device is obtained by depositing WS2nanosheet layers onto a 20 μm thick one-layer FM substrate using a thermal decomposition method. The modulation depth (MD) of the SA is 8.22% and the non-saturable loss (NL) is 16.38%. By inserting the SA into the EDF laser cavity, stable Q-switched operation is achieved with a central wavelength of 1567 nm. The repetition rate can be tuned from 20.98 kHz to 33.74 kHz and the pulse duration can be adjusted from 8.3 μs to 6.98 μs by increasing the pump power. The maximum output power and the maximum pulse energy are measured to be 2.07 mW and 61.4 nJ, respectively. The experimental results evidently show that the WS2/FM can be regarded as a high-performance SA for fiber lasers. ? 2016 Astro Ltd.
Accession Number: 20164102883048
-
Record 202 of
Title:High-sensitivity plasmonic sensor based on perfect absorber with metallic nanoring structures
Author(s):Lu, Xiaoyuan(1); Wan, Rengang(1); Liu, Feng(1); Zhang, Tongyi(1)
Source: Journal of Modern Optics Volume: 63 Issue: 2 DOI: 10.1080/09500340.2015.1066459 Published: January 19, 2016
Abstract:We propose a nanoring array structure backed by a metal mirror to achieve perfect infrared absorber with absorption as high as 99.99%. The frequency of the absorption peak strongly depends on the refractive index surrounding the structured surface, while the maximum of absorption remains constant with varying the surrounding refractive index. These features can be used as plasmonic sensor for refractive index measurement. This plasmonic sensor possesses the figure of merit 700. In addition, we investigate the effect of various materials on the performance of the sensor, including, TiN, and dielectric spacer and Au, Ag, Al, and Cu back plate and top structure. Due to the high sensitivity and simple sensing scheme, the sensing strategy can find potential applications in chemical and biosensor applications. ? 2015 Taylor & Francis.
Accession Number: 20153301176422
-
Record 203 of
Title:Generation of cylindrical vector beams based on common-path interferometer with a vortex phase plate
Author(s):Liang, Yansheng(1); Yan, Shaohui(1); Yao, Baoli(1); Lei, Ming(1); Min, Junwei(1); Yu, Xianghua(1)
Source: Optical Engineering Volume: 55 Issue: 4 DOI: 10.1117/1.OE.55.4.046117 Published: April 1, 2016
Abstract:Cylindrical vector (CV) beams have found increasing applications in physics, biology, and chemistry. To generate CV beams, interferometric technique is popularly adopted due to its flexibility. However, most interferometric configurations for the generation of CV beams are faced with system instability arising from external disturbance, limiting their practical applications. A common-path interferometer for the generation of radially and azimuthally polarized beams is proposed to improve the system stability. The optical configuration consists of a vortex phase plate acting to tailor the phase profile and a cube nonpolarizing beamsplitter to split the input beam into two components with mirror-like spiral phase distribution. The generated CV beams show a high quality in polarization and exhibit a better stability of beam profile than those obtained by noncommon-path interferometric configurations. ? 2016 Society of Photo-Optical Instrumentation Engineers (SPIE).
Accession Number: 20162102412270
-
Record 204 of
Title:A phase estimation algorithm for optical linear sampling
Author(s):Li, Fei-Tao(1,2); Zhao, Wei(1); Liu, Yuan-Shan(1)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 45 Issue: 8 DOI: 10.3788/gzxb20164508.0806002 Published: August 1, 2016
Abstract:An improved Blind Phase Search algorithm was proposed. In this algorithm, carrier phase noise was estimated by searching minimum Euler distance twice. To verify this algorithm, an optical linear sampling simulation system was set up. The constellation diagram of 10Gbaud/s 16QAM signal was simulated by using an optical frequency comb with pulse width of 500fs and duration of 10ns as optical sampling source. The simulation result shows that, the phase noise between the signal source and optical sampling source can be compensated effectively by this algorithm when the sum linewidth of the two lasers is less than 10MHz. Finally, the constellation diagram of 10Gbaud/s 16QAM signal is displayed clearly. ? 2016, Science Press. All right reserved.
Accession Number: 20163402737299
