2010
2010
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Record 217 of
Title:A near ultraviolet photon counting imaging detector
Author(s):Wei, Yonglin(1); Zhao, Baosheng(1); Sai, Xiaofeng(1); Liu, Yong'an(1)Source: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment Volume: Issue: DOI: 10.1016/j.nima.2010.10.085 Published:Abstract:Photon counting imaging detector is classified to direct collection mode and induction mode, based on the readout mode of microchannel plate (MCP) output charge. Previously, we discussed the detector with direct collection mode. A near ultraviolet (NUV) photon counting imaging detector with induction readout mode is presented here. The detector consists of a cesium telluride (Cs2Te) photocathode, a v-stack MCP, a semiconductor germanium layer on ceramic substrate, and wedge and strip anode (WSA). Quantum efficiency of the detector photocathode is 12% at (230 nm), dark count rate is 10.7 counts/(s cm2) and spatial resolution is 110 μm. ? 2010 Elsevier B.V. All rights reserved.Accession Number: IP51144812 -
Record 218 of
Title:Spectroscopic analysis of element concentrations in aluminum alloy using nanosecond laser-induced breakdown spectroscopy
Author(s):Luo, Wenfeng(1); Tang, Jie(1); Gao, Cunxiao(1); Wang, Haojing(1); Zhao, Wei(1)Source: Physica Scripta Volume: 81 Issue: 6 DOI: 10.1088/0031-8949/81/06/065302 Published: 2010Abstract:A plasma generated by 1064 nm Nd:YAG laser irradiation of aluminum alloy in air at atmospheric pressure was studied spectroscopically. The electron density was inferred by measuring the Stark broadened line profile of Cu(I) 324.75 nm, while the electron temperature was determined using the Boltzmann plot method with ten neutral iron lines. Based on the results, local thermodynamic equilibrium was studied. Moreover, calibration curves were presented for samples containing Si, Fe, Cu, Mn, Mg, Ni, Zn and Ti, and the limit of detection of trace elements was calculated based on experimental results. ? 2010 The Royal Swedish Academy of Sciences.Accession Number: 20102312999903 -
Record 219 of
Title:Tunable and switchable multiwavelength fiber lasers with broadband range based on nonlinear polarization rotation technique
Author(s):Li, Xiaohui(1); Liu, Xueming(1); Mao, Dong(1); Hu, Xiaohong(1); Lu, Hua(1)Source: Optical Engineering Volume: 49 Issue: 9 DOI: 10.1117/1.3485754 Published: September 2010Abstract:Switchable multiwavelength fiber laser outputs with a wide tuning range are experimentally observed in an ultralong cavity. Because of the long spooled single-mode fiber and filter effect of the cavity, multiwavelength lasers with the spacing of ～14.5 nm are obtained. The proposed fiber laser has the capacity of simultaneously emitting the three wavelengths. By means of adjusting the polarization controllers, the arbitrary single- and dual-wavelength operations are achieved in our laser. ? 2010 SPIE.Accession Number: 20114714538276 -
Record 220 of
Title:Transitional and steady mode-locking evolution of dissipative solitons
Author(s):Wang, Leiran(1); Liu, Xueming(1); Gong, Yongkang(1); Mao, Dong(1); Li, Xiaohui(1)Source: Applied Optics Volume: 49 Issue: 14 DOI: 10.1364/AO.49.002665 Published: May 10, 2010Abstract:We have experimentally observed the transitional and steady mode-locking (ML) evolution of dissipative solitons (DSs). It is found that pulses with different energies can coexist in the cavity during the evolution. When an additional pulse is generated from the laser, it initially exhibits weak intensity, and then gradually develops into the fully grown pulse with the increase of pump power. Meanwhile, the spectral profile of pulses is modulated at its top. The dynamic processes occur stage by stage, and can be regarded as the transitional states between the two nearby steady ML states. To our best knowledge, this is the first report on experimental observations for the detailed dynamic evolutions of pulse shaping in a DS laser. ? 2010 Optical Society of America.Accession Number: 20103513189027 -
Record 221 of
Title:Tunable band-pass plasmonic waveguide filters with nanodisk resonators
Author(s):Lu, Hua(1); Liu, Xueming(1); Mao, Dong(1); Wang, Leiran(1); Gong, Yongkang(1)Source: Optics Express Volume: 18 Issue: 17 DOI: 10.1364/OE.18.017922 Published: August 16, 2010Abstract:A novel and simple plasmonic filter based on metal-insulatormetal plasmonic waveguides with a nanodisk resonator is proposed and investigated numerically. By the resonant theory of disk-shaped nanocavity, we find that the resonance wavelengths can be easily manipulated by adjusting the radius and refractive index of the nanocavity, which is in good agreement with the results obtained by finite-difference time-domain (FDTD) simulations. In addition, the bandwidths of resonance spectra are tunable by changing the coupling distance between the nanocavity and waveguides. This result achieved by FDTD simulations can be accurately analyzed by temporal coupled mode theory. Our filters have important potential applications in high-density plasmonic integration circuits. ? 2010 Optical Society of America.Accession Number: 20103713224690 -
Record 222 of
Title:Broadly tunable dual-wavelength erbium-doped ring fiber laser based on a high-birefringence fiber loop mirror
Author(s):Sun, H.B.(1); Liu, X.M.(1); Gong, Y.K.(1); Li, X.H.(1); Wang, L.R.(1)Source: Laser Physics Volume: 20 Issue: 2 DOI: 10.1134/S1054660X10030175 Published: February 2010Abstract:A broadly tunable dual-wavelength erbium-doped ring fiber laser based on a high-birefringence fiber loop mirror (HiBi-FLM) and a polarization controller is demonstrated experimentally. The measured transmission spectrum of HiBi-FLM covers a wide range from 1525 to 1575 nm. The wavelength of proposed laser can be flexibly tunable during this range of ～50 nm by adjusting the polarization controller. In addition, the spacing of two wavelengths is adjustable by changing the length of HiBi fiber. The dual-wavelength lasers with the HiBi fiber length of 1 and 2 m are experimentally demonstrated and compared. The experimental results show that the proposed laser can stably operate on two wavelengths simultaneously at room temperature, and the output peak power variation is about 0.5 dB during 40 min. ? 2010 Pleiades Publishing, Ltd.Accession Number: 20101012754263 -
Record 223 of
Title:Second-harmonic generation from metal-film nanohole arrays
Author(s):Lu, Hua(1); Liu, Xueming(1); Zhou, Renlong(1); Gong, Yongkang(1); Mao, Dong(1)Source: Applied Optics Volume: 49 Issue: 12 DOI: 10.1364/AO.49.002347 Published: April 20, 2010Abstract:The roles of surface plasmon resonance and localized resonances in second-harmonic generation are investigated in a noncentrosymmetrical metallic film with a periodic subwavelength nanohole array. By using a recently developed microscopic classical theory and a three-dimensional finite-difference timedomain algorithm, numerical results show that the second-harmonic intensity is a function of the polarization and wavelength of incident waves. A peak of the second-harmonic intensity is achieved when the incident wave is along the direction perpendicular to the x-axis of nanoholes, which corresponds to the maximal extraordinary optical transmission. Meanwhile, the second harmonic is found to correlate with the group delay of incident waves. ? 2010 Optical Society of America.Accession Number: 20103413165681 -
Record 224 of
Title:Compact all-fiber high-energy fiber laser with sub-300-fs duration
Author(s):Liu, X.M.(1); Mao, D.(1)Source: Optics Express Volume: 18 Issue: 9 DOI: 10.1364/OE.18.008847 Published: April 26, 2010Abstract:We report a compact all-fiber high-energy fiber laser that consists of a laser oscillator and a compression section. The laser oscillator generates the pulses with high energy and large chirp. The compression section is made of a piece of standard single-mode fiber that dechirps the chirped pulses. The compact all-fiber fiber laser produces pulses with 8 nJ of the pulse energy and 290 fs of the pulse duration. ? 2010 Optical Society of America.Accession Number: 20101912924786 -
Record 225 of
Title:Mechanism of high-energy pulse generation without wave breaking in mode-locked fiber lasers
Author(s):Liu, Xueming(1)Source: Physical Review A - Atomic, Molecular, and Optical Physics Volume: 82 Issue: 5 DOI: 10.1103/PhysRevA.82.053808 Published: 2010Abstract:The mechanism and intrinsic conditions of high-energy wave-breaking-free pulse generation in fiber lasers mode-locked by a nonlinear polarization rotation technique are investigated numerically and experimentally. Both numerical and experimental results show that the pulses along the two orthogonal polarization axes of the fiber have a large difference in pulse energy. The numerical simulations show that the ratio of the energy of two components is limited and ranges from about 8 to about 65. The slope of the instantaneous frequency at the central position of the pulse decreases rapidly with the increase of the pulse duration and energy, whereas the slope at the pulse edge changes slightly. The accumulation of instantaneous frequency throughout the pulse width approaches a constant in a higher pulse energy regime. Understanding the mechanism and intrinsic conditions of the wave-breaking-free pulse generation could be useful in generating high-energy pulses delivered from fiber lasers. ? 2010 The American Physical Society.Accession Number: 20104913457850 -
Record 226 of
Title:Long-cavity passively mode-locked fiber ring laser with high-energy rectangular-shape pulses in anomalous dispersion regime
Author(s):Li, Xiaohui(1); Liu, Xueming(1); Hu, Xiaohong(1); Wang, Leirang(1); Lu, Hua(1); Wang, Yishan(1); Zhao, Wei(1)Source: Optics Letters Volume: 35 Issue: 19 DOI: 10.1364/OL.35.003249 Published: October 1, 2010Abstract:We report on a long-cavity passively mode-locked fiber laser in the anomalous dispersion regime. The nonlinear polarization rotation technique is employed to achieve mode locking. The output pulse from the fiber laser has a rectangular shape and a corresponding Gaussian-shape spectral profile. Stable mode-locked pulses at a repetition rate of 278 kHz with single pulse energy as high as 715 nJ are obtained under equal bidirectional pumping power of 500 mW in cavity. The experimental results demonstrate that the passively mode-locked fiber laser operating in the anomalous regime can also realize a high-energy pulse, which is different from the conventional low-energy soliton pulse. ? 2010 Optical Society of America.Accession Number: 20104513370072 -
Record 227 of
Title:Study of dielectric barrier discharge nonequilibrium plasma-assisted combustion for more efficient engine
Author(s):Tang, Jie(1); Duan, Yi-Xiang(1); Zhao, Wei(1); Luo, Wen-Feng(1)Source: Gaodianya Jishu/High Voltage Engineering Volume: 36 Issue: 3 DOI: Published: March 2010Abstract:The principle of activation of fuel or air by nonequilibrium plasmas is presented, and the probable process of formation of excited components that support the chain propagation reactions is discussed. The main body frame of nonequilibrium plasma reactor is put forward based on characters of the dielectric barrier discharge equipment with tube-tube configurations, and the feasibility of the design scheme is theoretically elucidated. Experiments on propane combustion were carried out using the nonequilibrium plasma reactor we designed. The experimental results show that nonequilibrium plasma can improve hydrocarbon combustion, and make it to be burnt more completely. The technology of nonequilibrium plasma-assisted combustion for more efficient engine is validated effectively.Accession Number: 20101912923492 -
Record 228 of
Title:Hysteresis phenomena and multipulse formation of a dissipative system in a passively mode-locked fiber laser
Author(s):Liu, Xueming(1)Source: Physical Review A - Atomic, Molecular, and Optical Physics Volume: 81 Issue: 2 DOI: 10.1103/PhysRevA.81.023811 Published: February 12, 2010Abstract:A model describing the dissipative soliton evolution in a passively mode-locked fiber laser is proposed by using the nonlinear polarization rotation technique and the spectral filtering effect. It is numerically found that the laser alternately evolves on the stable and unstable mode-locking states as a function of the pump strength. Numerical simulations show that the passively mode-locked fiber lasers with large net normal dispersion can operate on multiple pulse behavior and hysteresis phenomena. The experimental observations confirm the theoretical predictions. The theoretical and experimental results achieved are qualitatively distinct from those observed in net-anomalous- dispersion conventional-soliton fiber lasers. ? 2010 The American Physical Society.Accession Number: 20100712719513