2013
2013
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Record 361 of
Title:Theoretical analysis of scanning spectral filter method for coherent intensity contrast enhancement in femtosecond laser system
Author(s):Ma, Zai-Ru(1); Sui, Zhan(2); Zhou, Gui-Yong(1); Sun, Nian-Chun(3); Wang, Yi-Shan(4); Wang, Xiang-Lin(4); Zhang, Bin(2); Zhang, Rong-Zhu(3)Source: Wuli Xuebao/Acta Physica Sinica Volume: 62 Issue: 15 DOI: 10.7498/aps.62.154202 Published: August 5, 2013Abstract:A scanning spectral filter method is proposed for improving the intensity contrast originating from the phase ripple in the femtosecond chains, which is made using the character that the instantaneous frequency varies with the time approximately linearly for the chirped pulse in the time-frequency domain. The scanning spectral filtering for reducing the pre-pulse and post-pulse intensity is analyzed in the time-frequency domain by using the short-time Fourier transformation method. Results show that the coherent intensity pulse contrast can be improved by 0.41F2 for the chirped pulse or the compressed pulse, and the transmission efficiency of the chirped pulse can exceed 90% when the synchronizing time of the jitter ranges from -2 ps to 2 ps and the chirp rate p from 0.9 C/T2 to 1.1C/T2. ? Chinese Physical Society.Accession Number: 20133516678484 -
Record 362 of
Title:A synthetic aperture telescope based on a pair of gratings
Author(s):Ji, Ke(1,2); Gao, Peng(2); Min, Junwei(2); Guo, Rongli(2); Menke, Neimule(1,3)Source: Journal of Modern Optics Volume: 60 Issue: 15 DOI: 10.1080/09500340.2013.832428 Published: 2013Abstract:A synthetic aperture is an effective approach to enhancement of the resolution of telescopes. In this paper, a new method to improve the resolution by using a pair of gratings is proposed. It allows collection of parts of the light diffracted from the object which could not previously reach the imaging device. This method improves the resolution and light energy utilization ratio of telescopes without introducing new chromatic aberration. An experiment for resolution testing was carried out and the feasibility and availability of the method were verified. ? 2013 Taylor & Francis.Accession Number: 20134817038435 -
Record 363 of
Title:Induced current measurement in bridgewire EED through infrared optical fiber image bundle
Author(s):Xin, Liwei(1); Wang, Tao(1); Tian, Jinshou(1); Yin, Fei(1); Hu, Yanan(1); Song, Zhenyu(2); Yang, Jin(1); Yin, Jingzhi(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8905 Issue: DOI: 10.1117/12.2033704 Published: 2013Abstract:While bridgewire electroexplosive device (EED) works in electromagnetic environment, conventional methods can introduce electromagnetism interference. A new method of measuring the induced current in EED is proposed in this article. It bases on infrared imagingto detect the inducting current from long distance and non-contact. The infrared optical fiber image bundle coupling with infrared CCD detector is used to detect the infrared images.At first, the thermal field images are acquired by infrared CCD detector. Then the value of weak induced current of corresponding bridgewire is further determined according to the relations of gray scale values and temperature, temperature and current. The experiment results show that bridgewire current is accurately measured by this method. This method offers a new way to evaluate electromagnetic effect of EED. ? 2013 SPIE.Accession Number: 20134817032714 -
Record 364 of
Title:An analog modulated simulation source for X-ray pulsar-based navigation
Author(s):Zhou, Feng(1,2); Wu, Guang-Min(1); Zhao, Bao-Sheng(2); Sheng, Li-Zhi(2,3); Song, Juan(2,3); Liu, Yong-An(2); Yan, Qiu-Rong(2); Deng, Ning-Qin(2,3); Zhao, Jian-Jun(1)Source: Wuli Xuebao/Acta Physica Sinica Volume: 62 Issue: 11 DOI: 10.7498/aps.62.119701 Published: June 5, 2013Abstract:In this paper a high resolution X-ray simulation source is proposed and designed to verify the navigation based on X-ray pulsar in the simulation experience system. The simulation source consists of an arbitrary signal generator and a grid controlled X-ray tube. According to the grid tube's characteristic curve, the data of the pulsar standard pulse template are converted. Then using the method of direct digital frequency synthesis, the converted data are synthesized to waveforms, called the analog modulated grid voltage. In the grid controlled X-ray tube, the grid voltage changes the number of electrons hitting on the target and controls the X-ray intensity. With an analog modulated pulse profile applied on the tube grid electrode, the tube will emit X-rays which will match photons' statistical distribution and simulate the X-ray pulsar profile extremely well. The properties of Crab pulsar simulation source are tested in X-ray pulsar navigation simulation experience system. The results of the test are as follows: Comparing the tested pulse profile with the standard pulsar profile, we have time correlation coefficient is 0.9774, and frequency correlation coefficient is 0.9853. The X-ray photon flux is 1.90 ph·cm2-·s-1, the pulsed fraction is 76.15%, and the half-width half maximum is 1.879 ms. These results show that the X-ray simulation source has several merits, such as: strong ability to simulate the X-ray, low cost and simple operation. So it is an important means for the improvement of X-ray pulsar navigation. ? 2013 Chinese Physical Society.Accession Number: 20132816496963 -
Record 365 of
Title:Polarization-dependent optical guiding in low repetition frequency femtosecond laser photowritten type II fused silica waveguides
Author(s):Li, Dongjuan(1,2); Lin, Ling(1,3); Lü, Baida(3); Cheng, Guanghua(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 33 Issue: 5 DOI: 10.3788/AOS201333.0532001 Published: May 2013Abstract:The dependences of self-assembled nanograting in fused silica on low repetition frequency femtosecond laser parameters and scanning parameters are investigated. The results show that the filling factor of nanograting for scanning path cross section depends on the writing parameters. The type II waveguide in fused silica can be written under some writing condition and shows polarization-dependent guiding properties. Similar polarization-dependent guiding properties with 100 kHz situation is proved in experiment by hexagonal structures assembled from type II traces. Ideal models of the cross-sectional refractive index profiles of type II waveguides and the hexagonal structures are constructed. Corresponding modes are simulated using the finite element analysis method. It is found that the polarization-dependent optical guiding properties of type II waveguides are due to polarization-dependent scattering of nanograting rather than form birefringence in theory and experiment.Accession Number: 20132616448274 -
Record 366 of
Title:Design of lens-hood in the space fisheye optical system
Author(s):Zhu, Qing(1); Zhang, Zhao-Hui(1); Zhang, Zhi(1); Yan, Aqi(1); Cao, Jian-Zhong(1); Zhang, Kai-Sheng(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8907 Issue: DOI: 10.1117/12.2032304 Published: 2013Abstract:Due to the extra wide field of view, fisheye optical systems are appropriately applied in space camera for scouting large-scale objects with near-distance. At the same time, because of the violent sunlight linger within the field of view more than other optical system and more stray light occur during the period, to design proper lens-hood can effectively reduce the sunshine time. Another distinct characteristic of fisheye optical system is the first protrude lens, which is contrived with negative focus to trace the ray with angle about even above 90 degree of incidence. Consequently, the first lens is in danger of damaging by scratching when operating the camera during the ground experiments without lens-hood. Whereas on account of the huge distortion which is the third mainly characteristic of fisheye optical system, to design appropriate lens-hood is a tough work comparing with other low-distortion optical system, especially for those whose half diagonal field is more than 90°. In this paper, an research carried out on the design lens-hood for fisheye is proposed. In the way of reverse ray-tracing, the location on the first lens and point-vector for each incident ray can be accurately calculated. Thus the incident ray intersecting the first lens corresponds to the boundary of the image sensor form the effective object space. According to the figure of the lens and the incident rays, the lens-hood can be confirmed. In the proposed method, a space fisheye lens is presented as a typical lens, whose horizontal field and vertical field are 134°, diagonal field is up to 192°, respectively. The results of design for the lens-hood show that the lingering time of sunshine is shorten because of obstructing some redundant sunlight, and the first outstanding lens are protected in the most degree. ? 2013 Copyright SPIE.Accession Number: 20141317510109 -
Record 367 of
Title:Spectroscopic properties of ZrF4-based fluorophosphate laser glasses with large stimulated emission cross-section and high thermal stability
Author(s):Zheng, R.L.(1); Wang, P.F.(2); Xu, S.N.(2); Wei, W.(1,2); Peng, B.(1,2)Source: Laser Physics Volume: 23 Issue: 4 DOI: 10.1088/1054-660X/23/4/045805 Published: April 2013Abstract:A new kind of ytterbium-doped ZrF4-based fluorophosphate glass (FPZ), with large stimulated emission cross-section and high thermal stability, is prepared by introducing heavy metal oxides (HMO). The effects of HMO on glass structure, spectra and fluorescence are examined by Raman spectra, absorption and emission spectra. The result shows that the peak values of integrated absorption and emission cross-sections of the sample FPZ-6 are 7.15 × 104 pm3 and 1.29 pm2, with a lifetime of 1.51 ms and a ΔT(Tx - Tg) of 179.4 °C, implying that the novel FPZ glasses have potential applications as gain media in high-power lasers and fiber lasers. ? 2013 Astro Ltd.Accession Number: 20132616444984 -
Record 368 of
Title:Design and optimization of slow light photonic bandgap fiber
Author(s):Yun, Maojin(1); Liang, Jian(1,2); Ren, Liyong(2); Kong, Weijin(1); Wan, Yong(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 33 Issue: 4 DOI: 10.3788/AOS201333.0406005 Published: April 2013Abstract:A novel type of photonic bandgap fiber (PBG-PCF) applied to pulse and slow light is proposed. The designed PBG-PCF is composed of a hollow core and seven cladding layers with air hole arranged by triangular lattice. Its band structure, group index and group velocity dispersion are analyzed in detail by using plane wave expansion method. The simulation results show that slow light property can be improved effectively by microfluid infiltration for the air holes of the inner cladding of PBG-PCF, and an ultra-wide-band photonic crystal slow light optical fiber with a group index of 6, a wide band more than 100 nm, which can transmit flat slow light, is realized. The designed PBG-PCF has promising and potential applications in communication networks, signal processing, optical sensors and nonlinear interactions.Accession Number: 20132116362329 -
Record 369 of
Title:Comparison of fused silica and oxyfluoride glass on laser induced initial damage morphology
Author(s):Cheng, Qiang(1,2); Huang, Jin(2); Zhou, Xinda(2); Sun, Laixi(2); Jiang, Xiaodong(2); Sui, Zhan(2); Hou, Chaoqi(3); Wei, Wei(1,3); Peng, Bo(1,3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8786 Issue: DOI: 10.1117/12.2019995 Published: 2013Abstract:A novel oxyfluoride glass (OFG) was prepared. The laser induced damage threshold (LIDT) of the novel OFG is 24.9% higher than fused silica under 355nm nanosecond laser irradiation by R-on-1 procedure. Characterization by optical microscope and scanning electron microscope shows that the initial damage morphologies of two kind of materials are significantly different. Experiment results indicate that the novel OFG can be a good candidate component material for high energy laser applications. ? 2013 SPIE.Accession Number: 20133616692157 -
Record 370 of
Title:Effects of Al2O3 on the thermal stability, glass configuration of Yb3 +-doped TeO2-K2O-ZnO- Al2O3 based tellurite laser glasses
Author(s):Wang, Pengfei(1); Wang, Cuicui(2); Li, Weinan(1); Lu, Min(1); Peng, Bo(1)Source: Journal of Non-Crystalline Solids Volume: 359 Issue: 1 DOI: 10.1016/j.jnoncrysol.2012.09.031 Published: January 1, 2013Abstract:A novel of Yb3 +-doped TeO2-K2O-ZnO- Al2O3-based tellurite glasses with both good thermal stability and high-emission cross-section was prepared by verifying Al 2O3 additions. The changes in the thermal stability parameter ΔT (= Tx - Tg) and glass network configuration were investigated using differential scanning calorimeter (DSC) and Raman spectra measurements. DSC results show that the investigated tellurite glasses have favorite thermal stability for fiber drawing, and the maximum value of ΔT is up to 150°C. Raman spectra analysis indicates that the introduction of Al2O3 changes the polyhedron structural units of Te from TeO4 to TeO3 + 1, and in a further step to TeO3 configuration. The substitution of ZnO by Al 2O3 increases the glass's network connectivity, resulting in improvement of the glass's thermal stability and increase of the emission cross-section of Yb3 + ions in the glasses. ? 2012 Elsevier B.V.Accession Number: 20124815740800 -
Record 371 of
Title:The application of PSD in vibration measurment
Author(s):Zhu, Yuan Tao(1); Wang, Tao(1); Yin, Fei(1)Source: Applied Mechanics and Materials Volume: 380-384 Issue: DOI: 10.4028/www.scientific.net/AMM.380-384.820 Published: 2013Abstract:Position Sensitive Detector (PSD) is a new type of photoelectric position sensor. Compared with traditional CCD, PSD has high position resolution, simple circuit and fast response. Operational principle of PSD and how it can be used in vibration system are firstly shown in this paper. B ased on the MCU, a vibration measurement system using a B OS-PSD0220 type sensor is designed. The system is then experimentally measured at the most sensitive area of PSD. The result is compared with data calculated by MATLAB LE, which demonstrates PSD is a good choice for vibration measurement. ? (2013) Trans Tech Publications, Switzerland.Accession Number: 20134116828740 -
Record 372 of
Title:A study on the application of ICCD in low light level remote sensing
Author(s):Bai, Zhe(1); Zhang, Jian(1); Fan, Xue-Wu(1); Yang, Wen-Gang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8912 Issue: DOI: 10.1117/12.2034745 Published: 2013Abstract:Image intensifiers are always used to amplify low light level (LLL) images in a wide wavelength range to observable levels. As a leader in image intensifiers for industrial and scientific applications, intensified CCD (ICCD) is an innovative product which is a hybrid of image intensifier and CCD. Over the past few decades ICCDs have been increasingly developed and widely used in a variety of fields such as LLL television system and medical diagnostics. In this paper, we present the application of ICCD in the field of LLL remote sensing. General LLL imaging devices are introduced briefly, and their advantages and disadvantages are compared. ICCD technology which includes fundamental, configuration and development, is expatiated on. The major parameters which incarnate the performance of the LLL remote sensing ICCD camera are analyzed in detail, such as signal noise ratio (SNR), dynamic range, spatial resolution, etc. An ICCD camera is designed, and an imaging experiment is made to validate the imaging ability of it in LLL condition. The experiment results are discussed and summarized. At last, the most important issues to the application of ICCD in LLL remote sensing are generalized in detail. ? 2013 SPIE.Accession Number: 20141317521647