2014
2014
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Record 265 of
Title:Stabilizing the optical parametric oscillator cavity by fringe-locking technique in preparation of squeezed state of light
Author(s):Qu, Wen-Yan(1,2); Song, Jia-Zheng(1); Feng, Fei(1); Xue, Yu-Lang(1); Zhang, Tong-Yi(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 43 Issue: 9 DOI: 10.3788/gzxb20144309.0914004 Published: September 1, 2014Abstract:A fringe-locking technique was employed to stabilize the optical parametric oscillator cavity, which would be affected by external environmental disturbance, such as vibration and airflow. First, how the locking point influence the squeezing degree was analyzed theoretically, the results show that position at half of the transmission peak could be the best locking point. Then the fringe-locking technique was applied to achieve the resonance between the optical parametric oscillator cavity and the injected infrared light experimentally. The experimental results show that the length variance of the cavity in continuous operation over 2 h is 7.27 nm and the longest locking time is 3.8 h, which is sufficient for the detection of the squeezed states of light.Accession Number: 20144500153452 -
Record 266 of
Title:A high-efficiency tunable polarization-insensitive wavelength convertor based on degenerate four-wave mixing in a highly nonlinear photonic crystal fiber
Author(s):Huang, Xinning(1,2); Xie, Xiaoping(1); Zhao, Wei(1); Han, Biao(1); Feng, Huan(1)Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 41 Issue: 5 DOI: 10.3788/CJL201441.0505005 Published: May 2014Abstract:A high-efficiency tunable polarization-insensitive all-optical wavelength convertor for 10 Gb/s return-to-zero on-off keying (RZ-OOK) signals using degenerate four-wave mixing (FWM) in a highly nonlinear photonic crystal fiber (PCF) is demonstrated. The residual birefringence in the 50 m dispersion-flattened PCF with 11 W-1·km-1 nonlinear coefficient guarantees the FWM-based wavelength conversion to be polarization-insensitive when the pump polarization is exactly at 45° to the birefringent axes of the PCF. Experimental results show that with 45° pump launch, the polarization dependence of FWM in the PCF can be decreased to less than 0.6 dB over the entire 25 nm conversion bandwidth. The optical signal-to-noise ratios (OSNR) of the converted signals are better than 40 dB and the conversion efficiencies are better than -15 dB over the conversion range with 10 Gb/s signal polarization-scrambled.Accession Number: 20142217774676 -
Record 267 of
Title:Multi-bit quantum random number generation by measuring positions of arrival photons
Author(s):Yan, Qiurong(1,2); Zhao, Baosheng(2); Liao, Qinghong(1); Zhou, Nanrun(1)Source: Review of Scientific Instruments Volume: 85 Issue: 10 DOI: 10.1063/1.4897485 Published: October 1, 2014Abstract:We report upon the realization of a novel multi-bit optical quantum random number generator by continuously measuring the arrival positions of photon emitted from a LED using MCP-based WSA photon counting imaging detector. A spatial encoding method is proposed to extract multi-bits random number from the position coordinates of each detected photon. The randomness of bits sequence relies on the intrinsic randomness of the quantum physical processes of photonic emission and subsequent photoelectric conversion. A prototype has been built and the random bit generation rate could reach 8 Mbit/s, with random bit generation efficiency of 16 bits per detected photon. FPGA implementation of Huffman coding is proposed to reduce the bias of raw extracted random bits. The random numbers passed all tests for physical random number generator. ? 2014 AIP Publishing LLC.Accession Number: 20144500162398 -
Record 268 of
Title:Laser pulse shaping technology based on semiconductor laser
Author(s):Lin, Ping(1,2); Liu, Baiyu(1); Gou, Yongsheng(1); Bai, Yonglin(1); Wang, Bo(1); Bai, Xiaohong(1); Qin, Junjun(1); Zhu, Bingli(1); Yang, Wenzheng(1); Zhu, Shaolan(1); Gao, Cunxiao(1); Ouyang, Xian(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 1 DOI: Published: January 2014Abstract:Pulse shaping technique is of great significance for high power laser facility. In this paper, a new method used in laser pulse shaping system was proposed. An arbitrary waveform generator was fabricated to generate shaping electrical pulse. GaAs Field Effect Transistor (FET) has good ability of generating voltage-controlled current and on-off characteristic, while the semiconductor laser contains direct modulate characteristic. The unit-pulse was generated based on the on-off characteristic of GaAs FET, and then the arbitrary waveform electrical pulse was generated by stacking a set of unit-pulses. Impedance tapered micro-strip line was designed to maintain the consistency of each unit-pulse. The arbitrary waveform electrical pulse was used as shaping electrical pulse to modulate the semiconductor laser directly to realize the laser pulse shaping. With this method, a laser pulse waveform was generated with duration less than 10 ns, 330 ps time-domain adjustment. The experiment results show that the shaped laser pulse is determined only by shaping electrical pulse.Accession Number: 20141017420250 -
Record 269 of
Title:Multifunction medical endoscope system with optical fiber temperature sensor
Author(s):He, Zhengquan(1); Zhou, Libin(2); Luo, Baoke(1); Hu, Baowen(1); Du, Xinchao(1); Li, Yulin(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9216 Issue: DOI: 10.1117/12.2074540 Published: 2014Abstract:Thermal therapy (or hyperthermia) is one of the effective operations for tumor treating and curing. As tumor tissues are more susceptible to heat than normal tissues, in thermal therapy operations, temperature on operation area is a crucial parameter for optimal treating. When the temperature is too low, the tumor tissues cannot be killed; otherwise, the temperature is too high, the operation may damage normal tissues around the tumor. During thermal therapy operation, the heating power is normally supplied by high-frequency EM field, so traditional temperature sensors, such as thermal couples, thermistors, cannot work stably due to EM interference. We present a multi-function endoscope optical fiber temperature sensor system. With this sensor setup based on principle of fluorescence life time, the temperature on operation point is detected in real time. Furthermore, a build-in endoscope centers in the fiber sensor, thus the operation area can be viewed or imaged directly during the operation. This design can navigate the operation, particularly for in vivo operations. The temperature range of the sensor system is 30°C-150°C, the accuracy can achieve to 0.2°C. The imaging fiber buddle is constituted of more than 50k fibers. As the sensor probe is very thin (around 4 mm in diameter), it can also be assembled inside the radiofrequency operation knife. With the presented sensor system in clinic operation physicians can check the temperature in the operation point and view the operation area at the same time. ? 2014 SPIE.Accession Number: 20150800542550 -
Record 270 of
Title:Compact symmetric-type modulating technique of electron packet width
Author(s):Wang, Chao(1); Li, Hao(1,2); Tian, Jinshou(1)Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams Volume: 26 Issue: 3 DOI: 10.3788/HPLPB201426.034007 Published: March 2014Abstract:Aiming at the urgent needs for modulation technique of electronic packet width, we propose a compact symmetric type electron packet width modulation technique. The core of which is the introduction of the carefully chosen alternating electric field, which imposes differential energy modulation on electrons of different part in the electron packet, achieving the purpose of modulating the width of the electron packet. The details are given, including the choosing of the alternating electric field, pulse modulation amplitude relationship and the transverse confinement of the axial magnetic field. The requirements for both compression and broadening modulation in different types of modulating electric field are obtained. The example demonstrates its validity.Accession Number: 20141517567158 -
Record 271 of
Title:Accelerating beams with non-parabolic trajectories
Author(s):Yan, Shaohui(1); Li, Manman(1,2); Yao, Baoli(1); Lei, Ming(1); Yu, Xianghua(1,2); Qian, Jia(1,2); Gao, Peng(1)Source: Journal of Optics (United Kingdom) Volume: 16 Issue: 3 DOI: 10.1088/2040-8978/16/3/035706 Published: March 2014Abstract:We present a family of one-dimensional accelerating beams in the paraxial limit whose trajectory is described, in normalized coordinates (ξ, s), by a non-parabolic curve ξ = α(s) with α(s) denoting the transverse shift of beams. When taking different values of the parameters appearing in α(s), three types of accelerating beams are observed. The first type accelerates initially along X direction and almost stops accelerating after traveling a large distance. The second type is seen to travel along a straight line with an angle with respect to the Z-axis at large distance. The beam of the last type is seen to leave initially upward and cross the Z-axis downward after traveling some distance. ? 2014 IOP Publishing Ltd.Accession Number: 20141117455969 -
Record 272 of
Title:Inscription of waveguides in terbium gallium garnet using femtosecond laser
Author(s):Long, Xuewen(1,2); Bai, Jing(1,2); Liu, Xin(1,2); Zhao, Wei(1); Cheng, Guanghua(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 34 Issue: 4 DOI: 10.3788/AOS201434.0432002 Published: April 2014Abstract:Femtosecond-laser-photolithography is a flexible avenue to fabricate three-dimensional photonic devices in transparent materials. Terbium gallium garnet is widely used because of its Faraday rotation. Femtosecond laser operated at 1 kHz with a central wavelength of 800 nm is used to write double line waveguide and circular depressed-cladding waveguide in terbium gallium garnet. The distributions of refractive index change are reconstructed, and propagation losses of the waveguides are measured. Only the double line waveguide shows polarization dependent optical guiding. The magneto-optic response of the waveguides is determined. The rotation of plane of polarization cannot be occurred in double line waveguide under externally applied magnetic field ascribed to the phase mismatch of transvers electric (TE) mode and transverse magnetic (TM) mode. For the circular depressed-cladding waveguide, the plane of polarization is rotated under applied magnetic field. The inscribed double line and circular depressed-cladding waveguide in terbium gallium garnet are candidates for waveguide polarizer and magneto-optic device respectively, which are valuable for integrated optics.Accession Number: 20142117743291 -
Record 273 of
Title:Intrinsic optical torque of cylindrical vector beams on Rayleigh absorptive spherical particles
Author(s):Li, Manman(1,2); Yan, Shaohui(1); Yao, Baoli(1); Lei, Ming(1); Yang, Yanlong(1); Min, Junwei(1); Dan, Dan(1)Source: Journal of the Optical Society of America A: Optics and Image Science, and Vision Volume: 31 Issue: 8 DOI: 10.1364/JOSAA.31.001710 Published: August 1, 2014Abstract:The intrinsic optical torque of a focused cylindrical vector beam on a Rayleigh absorptive spherical particle is calculated via the corrected dipole approximation. Numerical results show that, for the radially polarized input field, the torque is distributed in the focal plane strictly along the azimuthal direction anywhere except at the focus. This shows a completely different property from what is observed in the focusing of a circularly polarized beam, where a strong axial torque component arises. For other cylindrically polarized input fields, the torque tends to align itself along the radial direction, as the polarization angle (the angle between the electric vector and the radial direction) changes from 0° to 90°. When limited to considering the torque at the equilibrium position, we find that only for those input fields with polarization angles larger than 50°, the particle experiences a nonzero torque at its equilibrium position. This is verified by showing quantitatively the effects of the polarization angle on the magnitude and orientation of the torque at the equilibrium position. ? 2014 Optical Society of America.Accession Number: 20143418091908 -
Record 274 of
Title:Theoretical study on slow light in different structures of optical microfiber knot resonators (OMKRs)
Author(s):Xu, Yiping(1,2); Ren, Liyong(1); Ma, Chengju(1,2); Liang, Jian(1)Source: Optik Volume: 125 Issue: 12 DOI: 10.1016/j.ijleo.2013.11.056 Published: June 2014Abstract:Based on the light propagation theory of the single-ring optical microfiber knot resonator (OMKR), we further establish the similar theory for OMKRs with a parallel connection structure and that with a serial connection structure, respectively. The relationships of the output and the input light fields in different OMKRs are analyzed. Numerical simulations of the slow-light performances of the OMKRs with single ring, multi-parallel rings and multi-serial rings at the communication wavelength around 1550 nm are given and discussed. Compared with the single-ring OMKR, it is found that a large group time delay with very narrow bandwidth can be obtained in OMKRs with n-ring parallel connection structure, while a broadband group time delay can be achieved in OMKRs with n-ring serial connection structure. ? 2014 Elsevier GmbH. All rights reserved.Accession Number: 20142217757265 -
Record 275 of
Title:Experimental study of femtosecond laser written waveguide in Yb3+:phosphate glass and waveguide laser
Author(s):Bai, Jing(1,2); Long, Xuewen(1,2); Liu, Xin(1,2); Zhao, Wei(1); Hui, Rongqing(1); Cheng, Guanghua(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 34 Issue: 4 DOI: 10.3788/AOS201434.0432003 Published: April 2014Abstract:Femtosecond laser with repetition rate of 1 kHz, central wavelength of 800 nm and pulse width of 120 fs is used to write waveguides in Yb3+:phosphate glass, then near-field modes of waveguide written by different laser parameters are measured. The refractive index changes in the written region and mode field diameter as functions of writing parameters (scanning speed and writing pulse energy) are obtained, which show the writing window of waveguide formation in Yb3+:phosphate glass. The fluorescence spectra of the waveguide and the bulk material are tested and compared. Experimental results show that there is no difference in the fluorescence spectra of the waveguide and the bulk material with 20× objective lens, scanning speed of 20 μm/s and pulse energy of 1.8 μJ, the mode field diameter is 20 μm injected at 976 nm, the refractive index change is 2.7×10-4, and the fluorescence properities keep the same after femtoscecond laser effect. Stable and continuous wave (CW) Yb3+:doped waveguide laser is achieved in a Fabry-Perot cavity configuration by using dichronic mirror and 2% output coupler. An output with power of 2.9 mW at a central wavelength of 1031 nm is obtained.Accession Number: 20142117743292 -
Record 276 of
Title:Study on 1.19 and 1.36 μm fluorescence for Ho-doped water-free fluorotellurite glasses
Author(s):He, Jianli(1,2); Zhan, Huan(1,2); Zhou, Zhiguang(1); Zhang, Aidong(1); Lin, Aoxiang(1)Source: Optics Communications Volume: 320 Issue: DOI: 10.1016/j.optcom.2014.01.040 Published: June 1, 2014Abstract:To find more efficient materials for optical amplifiers, near-infrared spectroscopic properties of Ho-doped water-free fluorotellurite glasses 60TeO2-30ZnF2-10NaF (mol%, TZNF60) were investigated. Excited by an OPO laser system at 534 nm, intense 1.19 (Ho: I 6→I8) and 1.36 μm (Ho: (S2,F)→I) emissions in Ho3+ doped TZNF60 glasses were observed, and long directly measured lifetime at 1.19 μm is of 750-950 μs and of 32-44 μs for 1.36 μm, respectively, resulting from the absence of OH groups and the low phonon energy with the addition fluorides into tellurite oxide glasses. Among all the made Ho-TZNF60 samples, 1.00HoO-TZNF60 glass presents the strongest fluorescence with larger emission cross-sections of (0.63, 0.22)×10 cm at 1.2 and 1.36 μm, respectively. Therefore, it is regarded as a promising material for the development of optical amplification and laser operation at the relatively unexplored 1.2 and 1.36 μm regions. ? 2013 Elsevier B.V. All rights reserved. ? 2014 Elsevier B.V. All rights reserved.Accession Number: 20140817344588