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A compact Tirsapphire femtosecond pulse amplifier without stretcher at high repetition rate

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Chinese optics Letters 2003年第4期1卷 225-227页

作者：程光华于连君王屹山刘青陈国夫赵卫 State Key Laboratory of Transient optics and Technology Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi'an 710068

We report a simple approach to amplify Ti:sapphire femtosecond pulses to moderate energy levels by a chirped regenerative amplifier. The seed pulses are broaden naturally because of the material dispersion of system components in regenerative cavity. The off-focusing Ti:sapphire crystal avoids effectively the optical damage. It sustains amplification over a wavelength range from 775 nm to more than 810 nm with a birefringent filter and an oscillation bandwidth of 7.7 nm, and produces 2.1 ps chirped output pulse energy of 100 uJ at 1.1-mJ pumping energy. This system shows good performances in stability and efficiency with the benefits of two thin-film polarizers and TEMoo mode pumping laser.

关键词： A compact Tirsapphire femtosecond pulse amplifier without stretcher at high repetition rate it on with of high Ti 米米 into from than have

Monte Carlo Study on Focus Properties of Portable Ultrabright Microfocus X-Ray Sources

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Chinese Physics Letters 2006年第9期23卷 2368-2371页

作者：王凯歌王雷刘文清牛憨笨 institute of Optoelectronics Shenzhen University Shenzhen 518060 Anhui institute of optics and {2. mechanics Chinese Academy of Sciences Hefei 230031 xi'an institute of Applied optics Xi'an 710065

The construct and electrode potential of emitting systems are very important for the portable ultrahigh brightness microfocus x-ray sources. The ratio of Dw/H （Dw is the diameter of Wehnelt grid aperture and H is the setting height of the cathode） and the grid bias are determinative parameters for the emission current and focus properties of an electron beam. The Monte Carlo method is used to numerically calculate the electron beam trajectories within a microfocus x-ray tube. The calculated results indicate that an optimum source system with the electron beam focal spot diameter smaller than 10μm at the anode, reasonable short focal length of about 76mm and the cathode emission current of more than 30mA can be attained under conditions of Dw/H = 5 and grid bias Vg = -0.6 k V.

关键词： NANOTUBE

Group-delay Dispersion in Double-prism Pair and Limitation in Broadband Laser Pulses

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Chinese Journal of Lasers 2002年第5期11卷 40-44页

作者：程昭赵卫 Femtolasers Productions GmbH A -1040 Wien 奥地利 xi'an institute of optics and {2. mechanics The Chinese Academy of Sciences State Key Lab . of Transient Optics TechnologyCAS Xi'an 710068

A general expression of group delay dispersion is obtained without any approximation for a pair of double prisms with an arbitrary apex angle. This expression also includes the change of dispersion resulting from change in insertion of the prism material into the beam by translating prism-pairs. The high order dispersion can be calculated by means of this expression. The limitation for generation of negative group delay dispersion by use of prism pairs is presented for ultrashort laser pulses with broadband spectrum.

关键词： group delay dispersion prism pair compressor ultrashort laser pulses

A method for calculating the center position of collimated light

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Optoelectronics Letters 2008年第2期4卷 155-158页

作者： WU Guo-jun WU Ling-ling CANG Yu-ping HE Jun-hua DONG Wei-bin CHEN Liang-yi xi＇an institute of optics and {2. mechanics Chinese Academy of Science Xi ＇an 710119 China

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.

关键词：计算方法位势光学激光

2.-GHz optical pulse source based on cascaded electroabsorption modulators

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Chinese optics Letters 2007年第12期5卷 700-702页

作者：刘元山张建国赵卫 State Key Laboratory of Transient optics & Photonics Xi'an Institute of Optics & Precision MechanicsChinese Academy of SciencesXi'an 710068 Graduate School of the Chinese Academy of SciencesBeijing 100039 State Key Laboratory of Transient optics & Photonics Xi'an Institute of Optics & Precision MechanicsChinese Academy of SciencesXi'an 710068 Department of ElectricalComputerand Communications EngineeringLondon South Bank UniversityLondon SE16ENUK State Key Laboratory of Transient optics & Photonics Xi'an Institute of Optics & Precision MechanicsChinese Academy of SciencesXi'an 710068

A high-quality low-timing-jitter 2.-GHz optical pulse train is generated by using two cascaded sinusoidally driven electroabsorption modulators （EAMs） at very low bias voltage of -0.8 V in conjunction with atunable distributed feedback （DFB） semiconductor laser. An approximate transform-limited optical pulse, with the pulse width less than 7 ps, the spectral width of 0.3 nm, and the side-mode suppression ratio （SMSR） above 2. dB, is obtained by tuning the optical delay line.

关键词： Bias voltage Distributed feedback lasers Electroabsorption modulators Semiconductor lasers Timing jitter

Adsorption and Reaction of CO on （100） Surface of SrTiO3 by Density Function Theory Calculation

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Chinese Physics Letters 2008年第9期25卷 3364-3367页

作者：贠江妮张志勇张富春 School of Information Science and Technology Northwest University Xi'an 710127 xi'an institute of optics and {2. mechanics Chinese Academy of Sciences Xi'an 710068

Adsorption and reaction of CO on two possible terminations of SrTiO3 （100） surface are investigated by the first-principles calculation of plane wave ultrasoft pseudopotentiai based on the density function theory. The adsorption energy, Mulliken population analysis, density of states （DOS） and electronic density difference of CO on SrTiO3 （100） surface, which have never been investigated before as far as we know are performed. The calculated results reveal that the Ti-CO orientation is the most stable configuration and the adsorption energy （0.449eV） is quite small. CO molecules adsorb weakly on the SrTiO3 （100） surface, there is predominantly electrostatic attraction between CO and the surface rather than a chemical bonding mechanism.

关键词： the power-law exponents precipitation durative abrupt precipitation change

Non-geometrical effects on Gaussian beams transmitting through a thin dielectric slab

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Chinese Physics B 2008年第5期17卷 1758-1768页

作者：李春芳张妍陈玺朱绮彪 Department of Physics Shanghai University State Key Laboratory of Transient optics Technology Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences

It is shown that a Gaussian light beam transmitting through a planar thin dielectric slab in the air undergoes four different effects, i.e. lateral Goos-Hanchen-like （GHL） displacement, angular deflection, width modification and longitudinal focal shift as compared with the results predicted by geometrical optics. According to the Taylor expansion of the exponent of transmission coefficient when expressed as an exponential form, the lateral GHL displacement and the angular deflection are the first-order effects and can be negative or positive. The width modification and the longitudinal focal shift are the second-order effects and can also be positive or negative. Owing to the waist-width dependent term, the non-geometrical effects of transmitted beam are not identical with the non-specular effects of reflected beam. The conditions for the validity of those effects are suggested and numerical simulations are also given.

关键词： non-geometrical effects finite-sized light beam beam transmission

CRT－LCLV　and　photorefractive　crystl　BSO　based　real－time　joint　transform　correlator

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Chinese Journal of Lasers 1994年第5期B3卷 463-468页

作者： FU xiaoli LI Yulin ZHANG Hai WANG Dayong(xian institute of optics & {2. beckonics, Academia Sinica,xian 710068, China) xi'an Inst of optics & precision Mechanics Academia Sinica Xi'an China

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关键词： hybrid optical pattern recognition joint transform correlator (JTC) spatial light modulator (SLM) photorefractive crystal

The Wavelength Shifting and Temperature Athermalization of Fiber Bragg Grating

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光学学报 2003年第S1期23卷 283-284页

作者： Yu'e Kong xi'an institute of optics and {2. mechanics of cas P. R. China 710068

The wavelength shifting properties and the temperature athermalization technology of fiber Bragg grating (FBG) were studied in this paper, and then two different athermalization methods were introduced. The research shows that FBG with athermalization by applying the substrate with negative coefficient of thermal expansion is effective and can be used in many fields.

关键词： Fiber Bragg grating negative coefficient of thermal expansion temperature athermalization