2013
2013
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Record 457 of
Title:All-optical EIT-like phenomenon in plasmonic stub waveguide with ring resonator
Author(s):Cui, Yudong(1); Zeng, Chao(1)Source: Optics Communications Volume: 297 Issue: DOI: 10.1016/j.optcom.2013.01.061 Published: June 15, 2013Abstract:An optical phenomenon analogous to electromagnetically induced transparency (EIT) has been proposed and investigated numerically in a plasmonic system, which is composed of a single stub-shaped metal-insulator-metal (MIM) waveguide coupled with a ring resonator. The transmission properties of the system are simulated by the finite-difference time-domain (FDTD) method. The bandwidth of the EIT-like spectrum is mainly dependent on the coupling distance between the stub and ring resonator. The red-shift of EIT-like peak is nearly linearly proportional to the increase in the radius and the refractive index of ring resonator, as is confirmed by the theoretical calculations. Our compact plasmonic structure may find potential applications in highly integrated optical circuits, such as nanoscale filters and optical switching. ? 2013 Elsevier B.V.Accession Number: 20131616218935 -
Record 458 of
Title:All-optical format conversion from non-return-to-zero to return-to-zero based on dual-pump four-wave mixing in photonic crystal fiber
Author(s):Hui, Zhan-Qiang(1); Zhang, Jian-Guo(2)Source: Wuli Xuebao/Acta Physica Sinica Volume: 62 Issue: 8 DOI: 10.7498/aps.62.084209 Published: April 20, 2013Abstract:A novel all-optical format conversion scheme based on dual-pump four-wave-mixing (DP-FWM) in dispersion-flattened highly nonlinear photonic crystal fiber (DF-HNL-PCF) is proposed and experimentally demonstrated. The original non-return-to-zero (NRZ) format is converted into double return-to-zero (RZ) format by injecting NRZ signal and double synchronized clock signals into the DF-HNL-PCF. The DP-FWM effect generates two sideband components, which carry the same data information as the original NRZ signal with RZ format. The wavelength tunability and dynamic range of format converter are investigated. The optimum extinct ratio and Q factor of converted signals are 15 dB and 5.4, respectively. The advantages of this scheme are that the each wavelength of double channel multicasting signals is dependent and flexible. Moreover, the system is transparent to bit rate as well as modulation format, and achieves all-optical wavelength conversion and wavelength multicasting. ? 2013 Chinese Physical Society.Accession Number: 20131916321612 -
Record 459 of
Title:The effect of additive on the performance and phase separation of benzo[1,2-b:3,4-b′]dithiophene-based polymer heterojunction photovoltaic devices
Author(s):Ni, Nan(1,2); Qu, Bo(3); Tian, Di(2); Cong, Zhiyuan(2); Wang, Weiping(2); Gao, Chao(2,4); Xiao, Lixin(3); Chen, Zhijian(3); Gong, Qihuang(3); Wei, Wei(1)Source: Macromolecular Chemistry and Physics Volume: 214 Issue: 9 DOI: 10.1002/macp.201200565 Published: May 14, 2013Abstract:An alternating copolymer (PBDTC10DBT) of benzo[1,2-b:3,4- b′]dithiophene (BDT) as donor and 4,7-di(3-decylthiophen-2-yl)-2,1,3- benzothiadiazole (C10DBT) as acceptor is designed and synthesized. In order to investigate the effect of the 1,8-diiodooctane (DIO) additive on the morphology and photovoltaic performance, polymer solar cells (PSCs) based on PBDTC10DBT:[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) are fabricated. The morphology of blend films and the interpenetrating network between the donor and the acceptor is examined using atomic force microscopy and scanning electron microscopy. This work shows that the PBDTC10DBT:PC61BM blend films with added DIO (3%, v/v) have improved absorption and controlled phase separation. Morphology with a domain size of 20-30 nm that forms in the DIO system is proposed to facilitate charge transport and minimize charge carrier recombination, which are the main reasons why the power conversion efficiency of the PSCs is improved from 1.93% (without DIO) to 2.23% (with DIO). An alternating copolymer (PBDTC 10DBT) of benzo[1,2-b:3,4-b']dithiophene (BDT) as donor and 4,7-dithiophene-2-yl-2,1,3-benzothiadiazole (DBT) as acceptor is synthesized. The influence of 3% (v/v) 1,8-diiodooctane on the absorption properties, the morphology of the active layer, and the photovoltaic properties is investigated. Copyright ? 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Accession Number: 20132016325862 -
Record 460 of
Title:High-power widely-tunable Tm:fiber master oscillator power amplifier
Author(s):Wang, Fei(1); Shen, Deyuan(1); Long, Jingyu(1); Wang, Yishan(1); Guo, Chengzheng(1)Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 40 Issue: 6 DOI: 10.3788/CJL201340.0602009 Published: June 2013Abstract:Tunable Tm:fiber lasers within a wavelength range around 2 m have numerous applications such as communications, lidar etc.. In this paper, a high power, widely-tunable Tm:fiber master oscillator power amplifier (MOPA) system is reported. The master oscillator is tunable over 160 nm (1921-2084 nm) by use of a diffraction grating, which is placed in the Littrow configuration to provide wavelength selective feedback. The MOPA laser is tunable over 140 nm (1936-2081 nm) and continuous-wave output power higher than 54 W is obtained over a tuning range of 100 nm from 1962 nm to 2066 nm, limited by the seed laser tuning range. The laser yields 77.4 W output power at 1981 nm, corresponding to a slope efficiency of 34.4%.Accession Number: 20133516678833 -
Record 461 of
Title:Multi-spectral dataset and its application in saliency detection
Author(s):Wang, Qi(1); Zhu, Guokang(1); Yuan, Yuan(1)Source: Computer Vision and Image Understanding Volume: 117 Issue: 12 DOI: 10.1016/j.cviu.2013.07.002 Published: 2013Abstract:Saliency detection has been researched a lot in recent years. Traditional methods are mostly conducted and evaluated on conventional RGB images. Few work has considered the incorporation of multi-spectral clues. Considering the success of including near-infrared spectrum in applications such as face recognition and scene categorization, this paper presents a multi-spectral dataset and applies it in saliency detection. Experiments demonstrate that the incorporation of near-infrared band is effective in the saliency detection procedure. We also test the combinational models for integrating visible and near-infrared bands. Results show that there is no single model to effect on every saliency detection method. Models should be selected according to the specific employed method. ? 2013 Elsevier Inc. All rights reserved.Accession Number: 20134416936251 -
Record 462 of
Title:Highly efficient pulse cleaner via nonlinear ellipse rotation in liquid CS2 for ultrashort pulses
Author(s):Liu, H.J.(1); Sun, Q.B.(1); Huang, N.(1); Wen, J.(1); Wang, Z.L.(1)Source: Optics Letters Volume: 38 Issue: 11 DOI: 10.1364/OL.38.001838 Published: June 1, 2013Abstract:A highly efficient pulse cleaner based on nonlinear ellipse rotation (NER) in a liquid medium of CS2 is investigated for the temporal contrast enhancement of ultrashort pulses. In theory, a nonlinear transmissivity higher than 60% can be achieved with the temporal contrast improved by about four orders of magnitude, on the condition that the extinction ratio of the polarizer-analyzer pair is better than 104. In a proof of principle experiment, the cleaned pulses at the mJ level with total transmissivity as high as 30% are obtained via NER, in which the temporal contrast is enhanced by about three orders of magnitude. This provides a simple and feasible technology for improving the temporal contrast of an ultrashort and ultraintense laser system in the future. ? 2013 Optical Society of America.Accession Number: 20132416413109 -
Record 463 of
Title:High conversion efficiency femtosecond optical parametric amplifier based on silicon waveguide in mid-infrared
Author(s):Wen, Jin(1); Liu, Hongjun(1); Huang, Nan(1); Sun, Qibing(1)Source: Optics and Laser Technology Volume: 50 Issue: DOI: 10.1016/j.optlastec.2013.02.017 Published: 2013Abstract:The mid-infrared femtosecond optical parametric amplifier (OPA) in silicon waveguide is proposed and investigated numerically. Through appropriately engineering the waveguide dimensions, the zero-dispersion wavelength of the silicon waveguide can be tailored to 2.1 μm and the broadband phase-matching can be realized. We achieve a conversion efficiency of -40 dB and a conversion bandwidth of over 300 nm for a low pump peak power in 8-mm-long silicon waveguide. We also analyze the evolution of the pump, signal and idler pulses in the process of optical parametric amplification. The proposed OPA exhibits compact configuration and can find important applications in integrated broadband optical source and ultrafast all-optical signal processing in mid-infrared. ? 2013 Elsevier Ltd. All rights reserved.Accession Number: 20131416157620 -
Record 464 of
Title:Crystallization and absorption properties of novel photo-thermal refractive glasses with the addition of B2O3
Author(s):Wang, Pengfei(1); Lu, Min(1); Li, Weinan(1); Gao, Fei(1); Peng, Bo(1)Source: Journal of Non-Crystalline Solids Volume: 368 Issue: 1 DOI: 10.1016/j.jnoncrysol.2013.03.002 Published: 2013Abstract:A new boron-containing photo-thermal-refractive (boron-PTR) glass was prepared by two-step melt-quenching techniques at relative lower glass melting temperature. The influence of Ag+ doping concentration, UV exposure dosage and thermal development parameters on the boron-PTR glass' spectroscopic absorption and crystallization property were investigated and compared with that of the known boron-free PTR glass explored by L. B. Glebov et al. The introduction of B2O3, to some extent, can increase the strength of the silicate bonding thus preventing the liquid-liquid phase separation in this new PTR system when compared to the boron-free PTR system. The developed boron-PTR glass with the processing of 15 s-UV exposure and appropriate thermal development (480 C/3 h, 500 C/2 h) exhibits good photo-induced crystallization performance, high VIS-near IR transmittance (670 to 2600 nm) and moderate photo-induced refractive index change (1.1 × 10- 3), which at present status enables this new PTR glass basic ability to record holographic elements. ? 2013 Elsevier B.V.Accession Number: 20131516188564 -
Record 465 of
Title:Error characteristics in mutual conversion process of reflective fiber optic current transducer's optical polarization state
Author(s):Wang, Lihui(1,2); He, Zhou(3); Liu, Xixiang(1); Yan, Jie(1); Li, Peijuan(1)Source: Diangong Jishu Xuebao/Transactions of China Electrotechnical Society Volume: 28 Issue: 1 DOI: Published: January 2013Abstract:Reflective fiber optic current transducer(R-FOCT) is a kind of precision instrument based on optical polarization and optical interference theory. The key optical components in R-FOCT show error characteristics in conversion between linear polarization state and circular polarization state, including quarter-wave retarder, sensing head and mirror, which induces linearly polarized light wave in polarization maintaining fiber and circularly polarized light wave in sensing fiber to be elliptically polarized light wave. Then nonreciprocal phase shift induced by magnetic field of the current is interrupted by wrong polarization state. Focused on polarization error characteristics during mutual conversion process in fiber optic current transducer, optical polarization error models are built by using Jones matrix and Poincare sphere respectively, investigated the influence of several key error factors on measurement accuracy and linearity of scale factor, including phase delay in quarter-wave retarder, birefringence in sensing head and mirror reflection phase shift error. Finally, the proposed methods are verified by simulation test, and scale factor error characteristics of R-FOCT related with optical polarization errors were quantified. The results verify the feasibility of the proposed research scheme.Accession Number: 20131116114414 -
Record 466 of
Title:Travelling wave deflecting characteristics of streak-tube
Author(s):Li, Hao(1,2); Tian, Jin-Shou(1); Li, Yan(3); Wang, Chao(1); Wen, Wen-Long(1); Wang, Jun-Feng(1); Wang, Xing-Chao(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 42 Issue: 7 DOI: 10.3788/gzxb20134207.0792 Published: July 2013Abstract:In order to obtain deflection device having wide bandwidth, small dispersion and high deflection sensitivity, a kind of traveling wave deflector is designed. Using commercial electromagnetic simulation software CST finite element method, bandwidth of traveling wave deflector in streak camera is studied, and the travelling wave deflector characteristics of dispersion curves, characteristic impedance changing with frequency and electron beam deflecting function are studied numerically using finite integration method. The comparison of deflecting sensitivity between traveling wave deflector and traditional plating deflector is made. Moreover, the electric field distribution in traveling wave deflector with sinewave scanning voltage signal is simulated. The results show that bandwidth of sharp top deflector is bigger than that of round top deflector and that bandwidth becomes smaller when legs of deflector become longer, with the biggest bandwidth of 7 GHz; phase velocity and group velocity decrease with the increasing of frequency; when frequency increases, a peak value exists for characteristic impedance; under the same dimensions, the deflecting sensitivity of travelling wave detector is two times higher than that of plating deflector; the electric field produced by sinewave scanning voltage appears periodic; the designed traveling wave deflector has wide bandwidth, of which dispersion is small in wide frequency range, and it can effectively make electron beam deflect.Accession Number: 20133416646437 -
Record 467 of
Title:Generation of high-energy and broadband terahertz radiation via coherent synthesis
Author(s):Li, Shaopeng(1); Liu, Hongjun(1); Huang, Nan(1); Sun, Qibing(1)Source: Journal of Physics B: Atomic, Molecular and Optical Physics Volume: 46 Issue: 24 DOI: 10.1088/0953-4075/46/24/245402 Published: December 28, 2013Abstract:A new method for the generation of high-energy and broadband terahertz (THz) radiation via coherent synthesis from multiple optical rectifications has been proposed. It is found that the intensities of the synthesized THz pulse are proportional to the square of the number of optical rectification processes when the same nonlinear crystals are used, which provides a simple method for the scaling up of THz energies with a powerful femtosecond laser. This method presents the possibility for THz strong-field physics with this table-top THz source. Moreover, in order to ensure that all the spectral components of the THz pulses are coherently synthesized, the relative time delay among the pump pulses should be less than 0.22 T0 (T0 is the pump pulse width). ? 2013 IOP Publishing Ltd.Accession Number: 20135217140185 -
Record 468 of
Title:High power operation of a tm-doped fiber laser with distributed pump configuration
Author(s):Long, Jing-Yu(1,2); Shen, De-Yuan(1); Wang, Yi-Shan(1); Zhao, Wei(1); Guo, Cheng-Zheng(1,3)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 42 Issue: 10 DOI: 10.3788/gzxb20134210.1147 Published: October 2013Abstract:In order to realize the high-power operation of the Tm doped silica fiber laser, there are two issues to be resolved. One is how to couple the pump light with low beam quality into the inner cladding of gain fiber efficiently, the other is on thermal management of gain fiber. For an efficient coupling, firstly the output beam of high power LD modules were collimated to reduce their beam diverge in the plane parallel to the array by use of a telescope system consisting of cylindrical aspheric lenses, and then the collimated beams were cut with splitters. The beam parameter in the plane parallel to the array was optimized to 84 mm·mrad (BPPx) after the reshaping, and a coupling efficiency of 70% was achieved by this means. A series connection structures consisting of two sections of Tm fiber with identical length were fabricated to increase available pump power and reduce the heat generation along the fiber ends, which achieved a total available pump power up to 580 W. With regard to the thermal management, each end section (250 mm long) of fibers was embedded in a V groove in a water cooled aluminum heat sink. Based on this configuration a continuous-wave output power of up to 280 W operating at 2015 nm was obtained for 6.4 m-long gain fiber, corresponding to a slope efficiency of 55.6% with respect to the launched pump power. The experimental results indicate that the special reshaping and laser configuration can improve pump coupling efficiency, reduce thermal loading and give more even axial temperature distribution along the gain fibers.Accession Number: 20135117103912