基于光纤Fabry-Perot滤波器的电光混合光学双稳态

提出了一种新型的电光混合光纤光学双稳装置,它由波长为1.55μm带尾纤的DFB半导体激光器、全光纤可调谐Fabry_Perot滤波器和电光反馈电路构成。实验中通过改变输入光强实现了光学双稳运转。讨论了该双稳器件在激光光强稳定器和光纤传感器方面的应用。     

Resonance-Radiation Force Exerted by a Circularly Polarized Light on an Atomic Wave Packet

We study the behaviour of an atomic wave packet in a circularly polarized light, and especially give the calculation of the radiative force exerted by the circularly polarized light on the atomic wave packet under the resonance condition. A general method of the calculation is presented and the result is interesting. For example, under the condition that the wave packet is very narrow or/and the interaction is very strong, no matter whether the atom is initially in its ground state or excited state, as time approaches to infinity, the resonance-radiation force exerted by the light on the atom approaches to zero. If the atom is initially in its ground state and excited state with the probability 1/2 respectively, and if the momentum density is a even function, then the resonance-radiation force exerted by the light on the atom is equal to zero.     

基于Fuzzy-P控制的半导体激光器功率稳定研究

为了提高光源抑制噪音的能力，提出一种基于模糊控制和比例控制的模数混合控制器，对中心波长为650 nm的半导体激光二极管的输出功率进行高准确度稳恒控制.实验结果表明，施加功率控制后，光源输出功率的静态稳定度达到±0.48‰，动态稳定度优于±1‰.     

A Measure of Non-Classicality of Even and Odd Coherent States

A measure of non-classicality of even and odd coherent states is studied. We first calculate the Wigner functions of the even and odd coherent states, which consists of two terms： the positive-definite Gaussian term and the wave term with negativity, and then calculate the integrated value εmax of the wave term of the Wigner functions of the even and odd coherent states in their area with negativity, and use εmax to measure non-classicality of the even and odd coherent states. For the even and odd coherent states with certain photon count, it is very convenient for us to use εmax to measure their non-classicality. The methods of our definition and calculation for εmax have theoretical reference value.     

Transverse Mode Formation in Longitudinally Pumped Miniature Slab Lasers

The formation of transverse modes in longitudinally pumped miniature slab lasers is investigated theoretically and experimentally. The longitudinally non-uniform gain-guiding is studied by expanding the electric field into the Hermite-Gaussian functions that satisfy boundary conditions of the resonator. Non-Gaussian transversal beam profiles in the near field are found and the beam diameter is reduced when the pump spot becomes smaller. The experimental observation agrees with the theoretical calculation.     

Forward-backward热方程差分逼近的直接算法

通过利用区域分解技术和并行算法的思想，把原问题分解为几个完全独立的子区域上的问题，并直接并行求解，然后把这些解作适当的线性组合，得到原问题的解，给出了Forward-backward热方程差分逼近的直接算法。     

50GeV北京质子同步加速器环境辐射安全的预评价

中国科学院准备建造的50 GeV质子同步加速器 (简称BPS) 的地点拟选在北京十三陵附近。这里是中国著名的文化古迹和游览区,周围有一些居民点,又处在首都的上风、上水方向。因而,加速器在这里建成运行后对环境的影响,尤其是在辐射方面的影响,是人们非常关心的。本文表明,BPS对其环境的辐射影响是非常小的,围墙外杂散辐射水平可保持低于20毫雷姆/年;采取某些防护措施后,其排放到大气中的短寿命放射性气体所造成的“浸没”剂量不超过10毫雷姆/年;进入水中的放射性物质,按很保守的估计,也不会使排出水的放射性浓度高于中国“放射防护规定”中所列适用于居民饮水的露天水源限制浓度的1/10。采取本文中建议的防护措施后,BPS不构成对环境的污染。本文是在参考欧洲核子研究中心(CERN)及其它高能加速器的经验的基础上,根据中国的有关标准或规定,以及加速器的设计参数,由高能所和CERN合作完成的。     

EXACT ANALYTIC METHOD FG(?) SOLVING VARIABLE COEFFICIENT DIFFERENTIAL EQUATION

Many engineering problems can be reduced to the solution of a variable coefficientdifferential equation.In this paper,the exact analytic method is suggested to solve variablecoefficient differential equations under arbitrary boundary condition.By this method.thegeneral computation format is obtained.Its convergence is proved.We can get analytieexpressions which converge to exact solution and its higher order derivatives uniformly.Four numerical examples are given,which indicate that satisfactory results can be obtauledby this method.     

关于微积分中值定理证明方法的注记

<正> 一般的微积分学课本,在证明拉格朗日(Lagrange)中值定理及柯西(Cauchy)中值定理时,都是采用作辅助函数的方法,其所用的辅助函数,就我们所见,有三种不同的类型([1]