电子束泵浦百焦耳级准分子激光实验研究

利用“闪光二号”相对论电子束加速器研制了百焦耳级ＸｅＣｌ和ＫｒＦ准分子激光器，激光器激活体积２４ｌ，输出口径２０×２０ｃｍ２，泵浦功率密度１．５～２．０ＭＷ／ｃｍ３。ＸｅＣｌ激光器最大能量１３６Ｊ，波长３０８ｎｍ，脉宽５０～１００ｎｓ，峰值功率１．５ＧＷ，采用虚共焦非稳腔技术，束散角达１．３ｍｒａｄ；ＫｒＦ激光最大能量１５７Ｊ，波长２４８ｎｍ，脉宽８０～１００ｎｓ，峰值功率２ＧＷ。     

轴向绝缘大面积二极管的研制

介绍了“天光一号”主放大器中的轴向绝缘大面积二极管的设计、机械结构及其特性的实验研究。结果表明,二极管能稳定的工作在峰值电压６００ｋＶ以上,电流密度能够达到８０Ａ／ｃｍ２,脉宽（ＦＷＨＭ）２２０ｎｓ,电子束总束能超过２５ｋＪ     

电子束泵浦KrF激光放大器增益与吸收的测量

为研制百焦耳级ＫｒＦ激光放大器，发展ＭＯＰＡ系统，我们用自探测法在百焦耳级电子束泵浦ＫｒＦ激光装置上进行了激光放大器的增益与吸收的测量。泵浦率约为０．６７ＭＷ／ｃｍ￣２，激光介质为８９．６％Ａｒ：１０％Ｋｒ：０．４％Ｆ＿２的混合气体，总气压０．２５ＭＰａ，实验测得激光放大器的小信号增益系数ｇ＿０＝６．６％ｃｍ￣（－１）、非饱和吸收系数α＿ｎ＝０．９３％ｃｍ￣（－１）、饱和光强Ｉ＿ｓ＝２．５ＭＷ／ｃｍ￣２。     

电子束泵浦KrF激光放大器增益与吸收的测量

为研制百焦耳级ＫｒＦ激光放大器，发展ＭＯＰＡ系统，我们用自探测法在百焦耳级电子束泵浦ＫｒＦ激光装置上进行了激光放大器的增益与吸收的测量。泵浦率约为０．６７ＭＷ／ｃｍ￣２，激光介质为８９．６％Ａｒ：１０％Ｋｒ：０．４％Ｆ＿２的混合气体，总气压０．２５ＭＰａ，实验测得激光放大器的小信号增益系数ｇ＿０＝６．６％ｃｍ￣（－１）、非饱和吸收系数α＿ｎ＝０．９３％ｃｍ￣（－１）、饱和光强Ｉ＿ｓ＝２．５ＭＷ／ｃｍ￣２。     

布鲁姆林线驱动被动紫外预电离KrF激光器

研制了一台水介质布鲁姆林线驱动被动紫外预电离放电泵浦ＫｒＦ准分子激光器，研究了其振荡和放大输出特性。在充电电压２５ｋＶ，工作气压０．２ＭＰａ，以振荡器工作方式输出激光能量近２００ｍＪ。以放大器方式工作时，注入激光脉宽２５ｎｓ，能量７０ｍＪ，放大输出达３３０ｍＪ。     

百焦耳级KrF准分子激光实验

介绍闪光Ⅱ号加速器泵浦的百焦耳级氟化氢激光研制情况，给出了激光器的构造和主要性能。在二极管电压为８４０ｋＶ，电流为２００ＫＡ条件下，获得了１５７Ｊ的最大激光能量，峰值功率为２．０ＧＷ。研究了激光输出能量随Ｆ２和Ｋｆ气体浓度的变化规律．     

宽频带KrF激光在SF_6介质中的SBS实验研究

宽频带ＫｒＦ激光泵浦高纯度高气压ＳＦ＿６气体产生了受激布里渊背向散射（ＳＢＳ）。实验研究了ＳＢＳ的强度和反射率随泵浦光强和ＳＦ＿６介质密度的变化，测得在ＳＦ＿６气压为１ＭＰａ时，泵浦光能量为１２０ｍＪ，ＳＢＳ光最大能量为１３ｍＪ，反射率为１０％，产生ＳＢＳ的泵浦光阈值１．１８×１０￣４ＭＷ／ｃｍ￣２。实验验证了ＳＢＳ光与泵浦光相位共轭特性，近场均匀性有很大改善，远场光束质量有一定改善，在泵浦光能量１３３ｍＪ，脉宽２５ｎｓ时，得到了脉宽６．８ｎｓ的ＳＢＳ光输出。脉宽压缩比为４。     

二极管激光侧面泵浦腔内倍频Nd：YAG板条激光器研究

用准连续６０Ｗ的二极管激光列阵侧面泵浦“之”字形Ｎｄ：ＹＡＧ板条激光器，当泵浦功率为４５Ｗ，脉宽为４００μｓ时，得到３．５ｍＪ的激光输出。用ＫＤ＊Ｐ电光开关调Ｑ，得到１８ｎｓ（ＦＷＨＭ）、２ｍＪ的脉冲激光输出，用ＫＴＰ晶体作腔内倍频，得到１５ｎｓ、０．８５ｍＪ的二次谐波激光输出。在腔内无调Ｑ元件且腔长小于５ｃｍ时，于近阈值处得到单频绿光输出，而当泵浦功率稍大，腔内有数个纵模振荡时，观察到激光的反相态，并用数值模拟的结果对此作了解释。     

高效率低阈值Nd：S－FAP晶体激光特性

测量了新型晶体Ｎｄ：Ｓ－ＦＡＰ［Ｎｄ：Ｓｒ＿５（ＰＯ＿４）＿３Ｆ］的吸收光谱特性，它具有宽的有效吸收带，在５７５．０ｎｍ和８０５．４ｎｍ处有二个强的吸收峰．用可调谐染料激光器测量了５７５．０ｎｍ处的吸收系数为１９．７ｃｍ￣（－１），用波长为５７５．０ｎｍ的的染料激光作泵浦源，实现了１．０５９μｍ的全偏振光输出，最低闽值为２．５ｍＪ，斜效率为４９％。用ＫＴＰ倍频获得的绿光的波长为０．５２９５μｍ，峰值半宽度为１．０ｎｍ。     

高质量的光刻胶图型及它对Nb／AlOx—Al／Nb隧道结制备的影响

本文用选择铌膜刻蚀或选择铌膜阳极氧化过程研究了全铌隧道结Ｎｂ／ＡｌＯｘＡｌ／Ｎｂ的制备．借助于ＳＥＭ，利用曝光后烘烤处理研究了高质量光刻胶图形的制备工艺，并分析了其对铌结特性的影响．结面积为７μｍ２的铌结具有典型的ＩＶ曲线，在４．２Ｋ时，他们的特性参数Ｖｍ～２０ｍＶ，能隙电压Ｖｇ～２．７ｍＶ，临界电流密度Ｊｃ～３０００Ａ／ｃｍ２，比电阻ρｎ～１μΩｃｍ２．这些铌结能够被直接应用于ｄｃＳＱＵＩＤ．     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.