2011
2011
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Record 289 of
Title:High average power, strictly all-fiber supercontinuum source with good beam quality
Author(s):Hu, Xiaohong(1); Zhang, Wei(1); Yang, Zhi(1); Wang, Yishan(1); Zhao, Wei(1); Li, Xiaohui(1); Wang, Hushan(1); Li, Cheng(1); Shen, Deyuan(1)Source: Optics Letters Volume: 36 Issue: 14 DOI: 10.1364/OL.36.002659 Published: July 15, 2011Abstract:A 1:05 μm picosecond pulsed fiber master oscillator power amplifier system delivering an average power of over 100W was used to pump a 5m long commercially available photonic crystal fiber and a 49:8W supercontinuum spanning from around 500nm to above 1700nm was generated. Strictly single mode operation of the all-fiber supercontinuum source across the whole spectral range was verified through the quantitative measurement of the beam quality. ? 2011 Optical Society of America.Accession Number: 20113014170676 -
Record 290 of
Title:Optical bistability in metal-insulator-metal plasmonic Bragg waveguides with Kerr nonlinear defects
Author(s):Lu, Hua(1); Liu, Xueming(1); Gong, Yongkang(1); Mao, Dong(1); Wang, Leiran(1)Source: Applied Optics Volume: 50 Issue: 10 DOI: 10.1364/AO.50.001307 Published: April 1, 2011Abstract:We numerically investigate the characteristics of the defect mode and the nonlinear effect of optical bistability in metal-insulator-metal (MIM) plasmonic Bragg grating waveguides with Kerr nonlinear defects. By means of finite-difference time-domain simulations, we find that the defect mode peak exhibits a blueshift and height-rise by enlarging the width of the defect layer, and it has a redshift and height-fall with the increase of the dielectric constant of defect layer. Obvious optical bistability is obtained in our waveguides with a length of less than 2 μm. The results show that our structure could be applied to the design of all-optical switching in highly integrated optical circuits. ? 2011 Optical Society of America.Accession Number: 20112414066669 -
Record 291 of
Title:Experimental observations of separation-changeable soliton pairs in a fiber laser mode-locked by nonlinear polarization rotation technique
Author(s):Li, Xiaohui(1); Liu, Xueming(1); Hu, Xiaohong(1); Wang, Leiran(1); Gong, Yongkang(1); Lu, Ua(1); Mao, Dong(1)Source: Journal of Optoelectronics and Advanced Materials Volume: 13 Issue: 3 DOI: Published: March 2011Abstract:The soliton pairs with changeable temporal separation in a passively mode-locked fiber laser are investigated experimentally. Temporal separations of pulses are as large as tens of nanoseconds, which are almost four orders of magnitudes larger than the pulse duration. The mechanism of the changeable separation mainly attributes to the variation of the linear phase delay in the cavity. Soliton pairs with large temporal separations and their variable characteristics are different from the operation of typical harmonic or bound state of solitons. These novel states in this report can be considered as the quasi-bound states.Accession Number: 20203409073302 -
Record 292 of
Title:Study on the transmission characteristic of terahertz pulse through packing materials
Author(s):Liu, Jia(1); Fan, Wenhui(1); Xue, Bing(1)Source: Chinese Optics Letters Volume: 9 Issue: SUPPL. 1 DOI: 10.3788/COL201109.S10202 Published: June 2011Abstract:Terrorism has become an international problem in recent years as evidenced by toxins mailed through the post, liquid explosives planted in airplanes, and so on. Clearly, the security screening of packing materials is highly required. We conduct nondestructive and contactless detection of some packing materials used in daily life by terahertz time-domain spectroscopy. The THz time-domain spectra of five typical kinds of packing materials are measured in the frequency range of 0.3-2.5 THz. THz absorption spectra and transmittance are also analyzed. ? 2011 Chinese Optics Letters.Accession Number: 20113214224365 -
Record 293 of
Title:Comment on "optical Orbital Angular Momentum from the Curl of Polarization"
Author(s):Yan, Shaohui(1); Yao, Baoli(1); Lei, Ming(1)Source: Physical Review Letters Volume: 106 Issue: 18 DOI: 10.1103/PhysRevLett.106.189301 Published: May 4, 2011Abstract:A Comment on the Letter by Xi-Lin Wang et al., Phys. Rev. Lett. 105, 253602 (2010)PRLTAO0031-900710.1103/PhysRevLett.105.253602. The authors of the Letter offer a Reply. ? 2011 American Physical Society.Accession Number: 20113014179399 -
Record 294 of
Title:Progress of NUV and FUV MCP-based photon-counting imaging detectors
Author(s):Liu, Yong-An(1); Zhao, Bao-Sheng(1); Wei, Yong-Lin(1); Sai, Xiao-Feng(1); Yan, Qiu-Rong(1); Sheng, Li-Zhi(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8196 Issue: DOI: 10.1117/12.900916 Published: 2011Abstract:In the World Space Observatory-Ultraviolet (WSO-UV) mission, the Long Slit Spectrograph (LSS) instrument will provide low resolution spectra in the range 102-320nm. Both the NUV (160-320nm) and the FUV (102-170nm) channels of LSS use microchannel plates (MCP) working in photon-counting modes as detectors. In this paper, the progress and parameters of NUV and FUV photon-counting imaging detectors were described. For the NUV detector, we developed the detector based on a sealed MCP-image intensifier which comprises input window, photocathode, MCP stack, Ge-layer and its ceramic substrate. To maximize the quantum efficiency, we adopted a Caesium Telluride (Cs2Te) photocathode, which was deposited on input window and mounted close to the MCP. For the FUV detector, because of the lower cut-off wavelength, there are no suitable window materials in this band and the open-faced design should be used to meet the requirements of the detection. Therefore, a Caesium Iodide (CsI) photocathode deposited on the input surface of the MCP was used to optimize detector efficiency. By using an existing wedge and strip anode (WSA), the imaging performance of the NUV and FUV detectors was tested respectively. Experimental results show that the quantum efficiency of Cs2Te is 12.1% (at 230nm), the spatial resolution of NUV and FUV detectors is better than 110μm, the dark count rate of NUV and FUV detectors is about 10.5- and 2.3-counts/s*cm2 respectively. ? 2011 SPIE.Accession Number: 20113614296286 -
Record 295 of
Title:Ultrawide tunable femtosecond optical parametric oscillator around 1.5 μm based on high nonlinear photonic crystal fiber
Author(s):Wen, Jin(1); Liu, Hongjun(1); Huang, Nan(1); Sun, Qibing(1); Long, Hanbo(1)Source: Optical Engineering Volume: 50 Issue: 8 DOI: 10.1117/1.3606497 Published: August 2011Abstract:The modulation instability and the phase-matching condition around the zero dispersion wavelength of the high nonlinear photonic crystal fiber (PCF) is numerically analyzed and simulated. The ultrawide tunable range can be obtained from the fiber optical parametric oscillator and the ultrashort pulse can be generated through choosing the parameters of dispersion coefficient, nonlinear coefficient, and pump power appropriately. The numerical simulation results show that a tunable range as wide as 318 nm has been obtained from the femtosecond PCF optical parametric oscillator, around 1.5 μm. ? 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).Accession Number: 20114714538346 -
Record 296 of
Title:Perfect absorber supported by optical Tamm states in plasmonic waveguide
Author(s):Gong, Yongkang(1); Liu, Xueming(1); Lu, Hua(1); Wang, Leiran(1); Wang, Guoxi(1)Source: Optics Express Volume: 19 Issue: 19 DOI: 10.1364/OE.19.018393 Published: September 12, 2011Abstract:Based on a two-dimensional plasmonic metal-dielectric-metal (MDM) waveguide with a thin metallic layer and a dielectric photonic crystal in the core, a novel absorber at visual and near-infrared frequencies is presented. The absorber spectra and filed distributions are investigated by the transfer-matrix-method and the finite-difference time-domain method. Numerical results show that attributing to excitation of the optical Tamm states in the MDM waveguide core, the optical wave is trapped in the proposed structure without reflection and transmission, leading to perfect absorption as high as 0.991. The proposed absorber can find useful application in all-optical integrated photonic circuits. ? 2011 Optical Society of America.Accession Number: 20113814337662 -
Record 297 of
Title:808 nm CW 2000 W semiconductor laser vertical stack
Author(s):Zhang, Entao(1); Zhang, Yanxin(1); Xiong, Lingling(1); Wang, Jingwei(1); Kang, Lijun(2); Yang, Kai(2); Wu, Di(2); Yuan, Zhenbang(2); Dai, Huabin(2); Liu, Xingsheng(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 40 Issue: 6 DOI: Published: June 2011Abstract:In order to promote the performance and power of high-power semiconductor lasers, double-faced thermal conduction technology was used, thermal design and packaging design were theoretically analyzed and optimized, which greatly improved the power of micro-channel water cooled vertical stack and single bar semiconductor lasers. The power of 808 nm 20 bars vertical stack semiconductor laser reaches 2000 W under the continuous wave (CW) condition, the average power of each bar reaches 100 W. The experimental data of LIV character, spectrum character, facula and smile of near field, the spreading angle and direction of semiconductor laser were obtained which showed the excellent performance of this semiconductor lasers. Also the life-time test experiment was carried out and the result shows the good performance. The high-power semiconductor lasers will be used in many application fields.Accession Number: 20113114199258 -
Record 298 of
Title:Realtime correction of probe pulse in subpicosecond time-resolved transient absorption spectroscopy
Author(s):Zhang, Su-Juan(1); Duan, Cun-Li(2); Feng, Xiao-Qiang(1); He, Jun-Fang(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8192 Issue: DOI: 10.1117/12.901003 Published: 2011Abstract:Due to its breakthrough the electro-optical time response limitation for picosecond dynamics of processes, many research groups around the world operating in different fields from physics and chemistry to biology, medicine and material science, utilize laser setups capable of providing subpicosecond pulses and femtosecond-level time delay lines. However the signal amount of Femto-picosecond Dynamics is about at an altitude of 1%, but the fluctuation of femtosecond probe pulse at its best can only reach about 5%. Real-time correct the probe pulse is the only effective way to realize subpicosecond time-resolved detection precision of transient absorption spectroscopy. So in this paper, reference pulse was drawn into the measurement equipment through different methods to dispel the fluctuation of probe pulse. Firstly, in the case of Subpicosecond time-resolved transient absorption spectroscopy, probe and reference beams have the same spectral distribution and derived from the same source to measure the variation of transmittance in the excited volume. Secondly probe pulse is spatially and temporally overlapped to the excitation pulse, reference pulse spatially overlapped but temporally anticipated in respect to the excitation pulse. Finally reference pulse passes through the sample in a different position. The detector can be a CCD camera or a double photodiode. The results shown that when reference pulse passes through the sample in a different position and detected by CCD, the correction results can reach to 1%. Which meet the femto-picosecond dynamics precise requirement. ? 2011 SPIE.Accession Number: 20113714320159 -
Record 299 of
Title:Terahertz TDS signal de-noising using wavelet shrinkage
Author(s):Liang, Yuqing(1); Fan, Wenhui(1); Xue, Bing(1)Source: Chinese Optics Letters Volume: 9 Issue: SUPPL. 1 DOI: 10.3788/COL201109.S10504 Published: June 2011Abstract:The field of terahertz (THz) science and technology has achieved significant progress over the last decades. Research interest focuses on THz spectroscopy and imaging. The signal-to-noise ratio (SNR) of the THz system is of great importance in the application of THz spectroscopy and imaging. In this letter, the wavelet de-noising technology is used to improve SNR and increase the speed of the THz time-domain spectroscopy system by reducing the repeating times. ? 2011 Chinese Optics Letters.Accession Number: 20113214224386 -
Record 300 of
Title:Numerical simulation of terahertz generation and detection based on ultrafast photoconductive antennas
Author(s):Chen, Long-Chao(1); Fan, Wen-Hui(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8195 Issue: DOI: 10.1117/12.900319 Published: 2011Abstract:The numerical simulation of terahertz generation and detection in the interaction between femtosecond laser pulse and photoconductive material has been reported in this paper. The simulation model based on the Drude-Lorentz theory is used, and takes into account the phenomena that photo-generated electrons and holes are separated by the external bias field, which is screened by the space-charge field simultaneously. According to the numerical calculation, the terahertz time-domain waveforms and their Fourier-transformed spectra are presented under different conditions. The simulation results indicate that terahertz generation and detection properties of photoconductive antennas are largely influenced by three major factors, including photo-carriers' lifetime, laser pulse width and pump laser power. Finally, a simple model has been applied to simulate the detected terahertz pulses by photoconductive antennas with various photo-carriers' lifetimes, and the results show that the detected terahertz spectra are very different from the spectra radiated from the emitter. ? 2011 SPIE.Accession Number: 20113614296190