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。     

北京谱仪上J/ψ→γπ~0、γη、γη—'→3γ衰变道的分支比测量

分析Ｊ／ψ衰变终态为三个光子的衰变道，测量得到了衰变道Ｊ／ψ→γπ０和Ｊ／ψ→γη’的分支比分别为Ｂｒ（Ｊ／ψ→γπ０）＝（４．６±１．１）×１０－５和Ｂｒ（Ｊ／ψ→ッη＇）＝（４．１２±０．８２）×１０－３；相对分支比Ｆ（Ｊ／ψ→γη’）／Ｆ（Ｊ／ψ→γη）＝４．７９±０．８５，在实验误差范围内与两个理论模型的预言都能一致。     

Dye Laser-pumped Cr: LiSrAIF_6 Laser

ＤｙｅＬａｓｅｒ－ｐｕｍｐｅｄＣｒ：ＬｉＳｒＡＩＦ_６Ｌａｓｅｒ￥ＷＵＸｉｎｇ（Ｄｅｐｔ．ｏｆＰｒｅｃｉｓｉｏｎＩｎｓｔｒｕｍｅｎｔＥｎｇｉｎｅｅｒｉｎｇ，Ｔｉａｎｊｉｎ３０００７２，Ｃｈｉｎａ）Ｔ．Ｏｋａｄａ，Ｋ．Ｋａｅｄａ（Ｄｅｐｔ．ｏｆＥｌｅｃ?..     

电源输出功率与效率的定量比较

在研究电源输出功率与效率的关系时,一般只做定性分析．本文试图对电源输出功率与效率做一般性定量比较．１　电源输出功率为最大时的条件１．１　输出功率如图１所示,电路消耗在负载电阻Ｒ上的功率可用下式表示：图１Ｐ＝Ｉ２Ｒ＝［Ｅ／（Ｒ＋ｒ）］２Ｒ＝Ｅ２Ｒ／［（Ｒ－ｒ）２＋４Ｒｒ］（１）……１．２　最大输出功率时的条件从（１）式可看出,仅当Ｒ＝ｒ时,Ｐ有最大值：Ｐｍａｘ＝Ｅ２／４ｒ２　输出功率与效率２．１　最大输出功率时的效率η＝ＰＰ总×１００％Ｐ总＝ＩＥ＝［Ｅ／（Ｒ＋ｒ）］Ｅ＝Ｅ２／（Ｒ＋ｒ）　　当电源有…     

球坐标系中矢量的微分

在球坐标（ｒ，θ，）中计算矢量的变化率，例如计算质点的加速度，需要先计算基底矢量ｅｒ，ｅθ，ｅ的微分ｄｅｒ ，ｄｅθ，ｄｅ，本文给出这三个微分．     

同一个非动力学r矩阵所对应的有理Ruijsenaars—Schneid …

构造了有理Ｒｕｉｊｓｅｎａａｒｓ－Ｓｃｈｎｅｉｄｅｒ模型（ｎ＝２）的新的Ｌａｘ算子,发现相应的ｒ矩阵是非动力学的,它与Ｃａｌｏｇｅｒｏ－Ｍｏｓｅｒ模型具有相同的ｒ矩阵。     

堆泵浦^3He—Ar—Xe体系的激光原理性实验

介绍了在ＣＦＢＲ－Ⅱ脉冲堆上进行的￣３Ｈｅ─Ａｒ─Ｘｅ体系的激光演示实验。当热中子注量率６×１０￣（１４）／ｃｍ￣２·ｓ，气体组配￣３Ｈｅ：Ａｒ：Ｘｅ＝３４．７：３４．７：０．２６７（ｋＰａ）时，获得波长λ＝１．７３μｍ、脉宽（ＦＷＨＭ）平均值７３８μｓ、峰值功率为毫瓦级的激光输出。同时对测得的光信号及其特性进行了分析。     

超球坐标下Li原子基态能量的快速收敛计算

将Ｌｉ原子２Ｓ态的波函数分解为两项之积，ψ＝ＸΦ，Ｘ＝ｅｘｐ［－α（ｒ１＋ｒ２＋ｒ３）］，而Φ向以九维超球谐为投影函数而构造的Ｓ３置换群的二维不可约表示的基函数展开。Ｓｃｈｒｏｄｉｎｇｅｒ方程转化为一起球径耦合微分方程。再利用广义Ｌａｇｕｅｒｒｅ函数展开法对其求解，从而得到一广义能量本征方程，给出了库仑势及有关超球角函数在非对称九维超球谐之间矩阵元的简单解析式，可由一起几何函数４Ｆ３：（Ａ，Ｂ，Ｃ，Ｄ；Ｅ，Ｆ，Ｇ；１）的线性组合表示。取超球谐函数的子集（ｌ１＝ｌ２＝ｌ３＝０），基态１２Ｓ的本征能量在超球角方向的收敛速度加快，首次用非变分法得到了优于Ｈａｒｔｒｅｅ－Ｆｏｃｋ精度的基态能量。结果表明本文给出的方法是对直接超球谐广义Ｌａｇｕｅｒｒｅ函数展开法（ＨＨ－ＧＬＦ）的一个非常有效的改进。     

堆泵浦~3He－Ar－Xe体系的激光原理性实验

介绍了在ＣＦＢＲ－Ⅱ脉冲堆上进行的￣３Ｈｅ─Ａｒ─Ｘｅ体系的激光演示实验。当热中子注量率６×１０￣（１４）／ｃｍ￣２·ｓ，气体组配￣３Ｈｅ：Ａｒ：Ｘｅ＝３４．７：３４．７：０．２６７（ｋＰａ）时，获得波长λ＝１．７３μｍ、脉宽（ＦＷＨＭ）平均值７３８μｓ、峰值功率为毫瓦级的激光输出。同时对测得的光信号及其特性进行了分析。     

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.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

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.     

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.     

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.     

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.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.