由双光子共振激发钾蒸气产生红外受激辐射以及紫外和可见相干辐射

当双光子共振激发钾原子到7S能级时,测得了一系列位于红外区的光泵受激辐射和串级受激辐射.由光泵受激辐射与泵浦光的双光子共振四波混频过程,产生了对应于6P-4S和5P-4S的强相干辐射.而这两个相干辐射又具有泵浦光的作用,通过接联的四波混频过程产生位于紫外和可见区的许多相干辐射.文中对测到的红外受激辐射以及紫外和可见相干辐射的产生过程进行了讨论.     

基于受激辐射信号的谱域光学相干层析分子成像方法

鉴于不同生理病理状态下组织复折射率实部的变化不大,传统光学相干层析(OCT)成像技术在分子特异性识别上存在先天不足.为此,本文提出了基于受激辐射信号的OCT成像方法,可在实现传统散射成像的同时,实现基于受激辐射信号的分子成像.在超高分辨率谱域OCT系统的基础上,通过增设光谱分光与调制抽运光支路,建立了基于单宽谱光源的抽运探测谱域OCT系统,详细推导了调制抽运下受激辐射信号的获取与成像公式.利用搭建的抽运探测谱域OCT系统,实现了瞬态受激辐射信号的相干探测.基于同时获取的受激辐射OCT信号和传统OCT信号,成功重构了氮化物粉末构建样品的基于受激辐射信号的分子对比OCT图像.     

共轭聚合物中受激吸收与受激辐射的量子动力学研究

基于扩展的一维SSH紧束缚模型结合非绝热的分子动力学方法,理论研究了共轭聚合物分子(PPV)在光脉冲作用下受激吸收和受激辐射的量子动力学过程.首先,设定分子初始处于基态,讨论了受激吸收过程中不同的电子受激跃迁模式与光激发脉冲的关系.通过对终态的分析,发现分子受激后只能产生电子-空穴的束缚态,包括:激子、双激子和高能激子.计算了各种激发态的产率,特别是,给出了各种激发态产率与光激发能量的定量关系.此外,基于实验,分别讨论了光激发强度对高能激子和双激子产率的影响,并与实验结果进行了比较.最后,设定分子初始分别处于激子和双激子态,研究了分子内定域能级之间的受激辐射过程,并简单讨论了激子和双激子受激辐射与光激发能量及强度的关系.     

驻波场中原子的跃迁速率与所受辐射受力的关系

从二能级原子的密度矩阵运动方程出发，研究了原子在驻波场中的受激吸收速率、受激辐射速率和辐射压力的对应关系，提出了在驻波场中原子所受的辐射压力由受激吸收力和受激辐射力构成。此观点可以推广至Ｎ个行波场和原子相互作用的情况。     

驻波场中原子的跃迁速率与所受辐射压力的关系

从二能级原子的密度矩阵运动方程出发,研究了原子在驻波场中的受激吸收速率、受激辐射速率和辐射压力的对应关系,提出了在驻波场中原子所受的辐射压力由受激吸收力和受激辐射力构成。此观点可以推广至N个行波场和原子相互作用的情况。     

电子-光子符合散射实验中受激原子态电荷云分布的研究

根据电子原子碰撞受激态退激偶极辐射的电子-光子符合实验的一般性理论，采用扭曲波近似方法，计算了电子与碱金属钠原子碰撞退激辐射光子的Stokes参数.引入取向和排列参数，用以描述受激态电荷云的分布，得到了与已有实验数据一致的结果. 关键词： 取向 排列 Stokes参数 电子-光子符合测量     

VPE ZnSxSe1-x外延膜中的自发和受激辐射

本文首次报道了VPE ZnSxSe1-x外延膜在77K时起因于激子和激子(Ex-Ex)散射的自发辐射和受激辐射,研究了Ex-Ex散射发光的位置和强度与激发密度的关系,分析了受激辐射的光子能量比自发辐射稍低的原因.     

北京自由电子激光装置的红外激光振荡实验

本文阐述了北京自由电子激光装置所采取的优化电子束质量等措施以满足出光条件,和利用这台装置相继观察到了自发辐射、储存自发辐射和受激辐射的情况.测定的受激辐射讯号的强度、光谱、失谐曲线和波长移动均证明其为红外自由电子激光振荡讯号.     

光腔中两组分玻色-爱因斯坦凝聚体的受激辐射特性和量子相变

研究了单模光腔中两组分玻色-爱因斯坦凝聚的基态性质和相关的量子相变.通过利用自旋相干态变换将等效赝自旋哈密顿算符对角化并求得基态能量泛函.基态能量泛函对其经典场变量进行变分并取极小值,得到光子数解和相边界曲线.通过稳定性讨论发现系统除了出现正常相和超辐射相之外,还得到了多稳的宏观量子态;受激辐射来自于原子数反转的集体态,单组分的Dicke系统中并没有此现象;受激辐射只能从一组分的原子中产生,而另外的仍保持在普通超辐射状态.通过调整相关的原子-场耦合强度和频率失谐,超辐射和受激辐射态的顺序可以在原子的两个组分之间互换.     

基于两步混合激发Na_2-Na系统的可调谐红外受激辐射

本文报道了与两步混合激发Na_2-Na系统相联系的受激电子喇曼散射过程产生了在3.38—3.46μm范围内连续可调谐的红外受激辐射的研究结果。对这种可调谐红外受激辐射的产生机制和实验结果作了仔细的分析和讨论。 同时,还计算了该红外受激辐射的相对强度并与实验结果进行了比较。最后指出这一工作与前人所做工作的不同之处及所具有的显著特点。     

On the interaction of stimulated spin-flip raman scattering and stimulated recombination radiation in InSb

We have studied the interaction of stimulated spin-flip Raman scattering and stimulated recombination radiation in n-InSb using a CW CO pump laser. A change in linewidth and output power of second Stokes spin-flip radiation is observed when the tuning curve of the first Stokes stimulated spin-flip radiation and the stimulated recombination radiation cross. The observations are explained using a simple rate equation model.     

An interaction of the stimulated spin-flip Raman scattering with the stimulated recombination radiation in InSb

We have observed an interaction of the stimulated spin-flip Raman scattering and stimulated recombination radiation in InSb. At magnetic fields, where these radiations have equal or nearly equal frequencies, we find an enhancement of the output power of stimulated spin-flip Raman radiation while the output power of recombination radiation decreases. This effect occurs with the first, the second and the third Stokes radiation.     

Investigation of mechanism of free electron laser through spontaneous radiation spectrum

In this paper, the mechanism of free electron laser with a guide magnetic field is investigated by analyzing spontaneous radiation spectrum of electrons. The physical relation between spontaneous radiation and stimulated radiation in FEL with a guide magnetic field is studied. It is found that this relation in FEL is similar to that in quantum lasers. The spontaneous radiation spectrum is discrete. The frequency of stimulated radiation in FEL is oneselected and amplified in the radiation spectrum.     

受激辐射压力的光子再分配模型

本文报道了在两束不同频率、不同传播方向的光束作用于二能级原子的受激辐射压力的数值结果。给出了一个新的模型——光子再分配模型——来解释受激辐射压力。     

钾原子中多种受激辐射参与的混频过程

当双原子共振激发钾原子于６Ｓ能级时,由光泵受激辐射和电离复合受激辐射参与的六波或四波混频,产生了位于紫外和紫区的诸多相干辐射、文中对多种混频机制进行了分析和讨论,并对所测得的相干辐射线进行了标识．     

锂蒸气中双光子泵浦的六波、四波混频和受激辐射

本文报道锂蒸气中由双光子泵浦所产生的位于紫外、可见和红外区的相干和受激辐射。包括:由一特殊六波混频过程产生的在1.03μm附近的可调谐相干辐射,由锂分子双光子离解或原子串级跃迁产生的波长为812.6nm的受激辐射,以及由四波混频产生的位于323.3nm和670.8nm的相干辐射。 关键词：     

Superradiant and stimulated superradiant emission in a prebunched beam free-electron maser

An electron beam, prebunched at the synchronous free-electron laser frequency and passing through a magnetic undulator, emits coherent (superradiant) synchrotron undulator radiation at the bunching frequency. If an external electromagnetic wave is introduced into the interaction region, at the same frequency and at a proper phase, the radiation process will be stimulated (stimulated prebunched beam radiation). We report first experimental measurements of stimulated superradiant emission in a prebunched free-electron maser. Measurements are in good agreement with theory.     

Phase of radiation from stimulated emission

With the help of the quantum theory of radiation, it is shown that the stimulated radiation from an atom has the same direction and phase dependence as the incident stimulating radiation.     

光纤中受激拉曼散射连续谱研究

我们在实验中研究了自相位调制效应和受激四光子混频效应对受激拉曼散射光谱的影响。在较强的泵浦光和适当的入射条件下,得到九阶受激拉曼散射的级联 Stokes 连续平滑谱带,带宽3500cm~(-1),其强度可与530nm 泵浦光强相比拟。     

Fundamental Studies of Stimulated Raman Scattering and Adaptive Optics on the Basis of Stimulated Light Scattering

Some results associated with the fundamental investigations of stimulated scattering of light in various media are reported. A number of problems of adaptive optics based on stimulated scattering is studied. Concrete results of experimental investigations of physically important characteristics of conventional (spontaneous) and stimulated Raman scattering are presented and discussed. Among them are the scattering indicatrix and the relations between the phases of laser radiation incident on a substance and stimulated scattering. These results were first obtained in the G. S. Landsberg Optical Department of the P. N. Lebedev Physical Institute of the Russian Academy of Sciences. Data on excitation sources and the radiation detection technique are systematized. The main characteristics of spontaneous Raman scattering and forward and backward stimulated Raman scattering (energy parameters, pulse duration, pulse shape, divergence, brightness, spectral width, far- and near-field intensity distributions) are presented. The results on dynamic holography, phase conjugation of light in stimulated scattering, and reconstruction and recording of information (images) with the help of amplifying dynamic holograms are presented. The physical mechanisms responsible for the interference field recording and the phase conjugation of pump radiation in stimulated light scattering are discussed. The data on phase conjugation for stimulated scattering excited by picosecond optical pulses and the results associated with the effect of excitation geometry on the optical phase conjugation in the case of stimulated scattering excited by nanosecond pulses are presented.