ICRF集体电子密度起伏的FIR激光散射

本文给出了在UCLA的Microtor装置上,用远红外(FIR)激光散射,对离子回旋共振频率范围(ICRF)的外驱动集体电子密度起伏的测量,并对这些结果进行了分析,发现实验结果直接与两种离子等离子体的快波模转换理论相符合。此外,也描述了本实验所用激光散射系统,简单地讨论了有待进一步探讨的问题。     

Study of the buckling mechanism in laser tube forming

The buckling mechanism of a thin metal tube during laser forming was investigated numerically and experimentally in this study. Metal tubes made of 304 stainless steel were heated by a CO₂ Gaussian laser beam, which induced the buckling phenomenon on the tube surface due to elastic–plastic deformation. This uncoupled thermal–mechanical problem was solved using a three-dimensional finite element method and was subsequently satisfactorily verified with displacement measurements. The transient bending angle and residual stress of the thin metal tube under specific operation conditions were also studied.     

激光气化进样等离子体发射光谱测定锡石中微量元素

采用自动设计、组装的激光气化等离子体发射光谱分析装置，系统地研究了单矿物锡石中２１种元素的蒸发、激发特性。将样品全蒸发输入ＩＣＰ激发，光谱测定，分析结果与经化学分离富集、ＩＣＰ－ＡＥＳ测定结果吻合。     

共振离子化质谱在高纯材料表面杂质分析中的应用

用激光熔出－共振离子化质谱法测定纯铁中及高纯硅片表面的铬。测定含有１０１２原子／ｃｍ２Ｃｒ的信号强度表明本方法可测定低至１０９原子／ｃｍ２的样品，其空间分辨率为０．２ｍｍ，还可进行二维杂质元素分析。     

Ar辅助确定Al等离子体电子温度

用Ar气作保护气时 ,Nd :YAG脉冲激光烧蚀Al靶 ,将诱发Ar气电离 ,并产生丰富的Ar离子谱线辐射。文章根据Ar离子谱线辐射信息 ,分析了ArⅡ 385 0 5 7,ArⅡ 386 85 3,ArⅡ 4 0 4 2 91 ,ArⅡ 4 0 7 2 0 1nm等 4条谱线的时间分辨行为 ,计算了Al等离子体的电子温度。结果发现 :Al等离子体的电子温度约 1 5 0 0 0～2 2 0 0 0K ,随延迟时间的增加 ,电子温度单调衰减     

铕（Eu）原子的激光增强电离光谱的研究

本文从激光增强电离光谱的速率方程和ＬＥＩ光谱加宽理论出发，得到ＬＥＩ光谱信号和光谱轮廓的表达式，在紫外区测得铕的三条ＬＥＩ谱线。并用计算机模拟光谱的方法给出这三条谱线的轮廓，与实验所得的谱图一致。     

高频半导体激光器组件及其特性的研究

本文使用ＤＣ－ＰＢＨ型激光二极管芯片，设计制作了实用化封装形式的激光器组件；在理论上和实验上研究了组件的封装模型和小信号频率调制特性，其光响应３ｄＢ带宽大于１．８ＧＨｚ。该器件可满足六次群的光通信系统的带宽要求，也可用于ＧＨｚ级的微波副载波光通信系统。     

A method of making a true color stereoscopic hologram

A true color stereoscopic hologram is made with one-wavelength laser. Under illuminating incandescent lamp, a true color stereoscopic image can be seen from the hologram. A diffused reference light and a project object light are used in the recording of the hologram. The three primary color images of natural scenery are encoded on a white-and-black film. With the help of the encoded film, a true color hologram is recorded on a plate by single exposure and a true color stereoscopic by two exposures. The simplification of this method is apparent. Further more, it largely decreases the scattering noise of the hologram and averts the problem of color lack fidelity of the holographic image.     

Modeling and experimental investigation of short pulse Raman microchip laser

The results of experimental and theoretical investigations of passive Q-switch Raman microchip lasers based on Nd³⁺:LSB active medium and Ba(NO₃)₂ Raman crystal are presented. It has been demonstrated that intracavity Raman conversion in the microchip lasers is a simple and efficient method, capable of delivering high power pulses with sub-100 ps duration. Intracavity generation of the 1st Stokes pulses with duration from 180 down to 48 ps and a peak power of 48 kW has been performed and studied. High peak power and short duration of the 1st Stokes pulses in microchip laser with Ba(NO₃)₂ Raman crystal allows to easily perform extracavity harmonic generation and frequency sum mixing in LBO, BBO, and KTP crystals with discrete-tunable wavelength from ∼1200 down to ∼240 nm. We have developed a generalized model of Q-switched Raman microchip lasers, that takes into account spatial inhomogeneity of pump, laser, and Stokes beams, thermalization within the upper and lower multiplets of activator ions in laser medium, and saturable absorber bleaching and recovery. For the microchip lasers with different saturable absorbers, the model achieves very good agreement with the presented experimental results in a wide range of pump powers.     

High efficiency long pulse FIR Raman conversion in ammonia

Generally the quantum efficiency of FIR Raman generation in molecular gases is below the theoretical value. This disagreement is particularly evident in Raman scattering from pulsed sources with short pulse length, when the vibrational saturation limits the power conversion. Other nonlinear processes can overcome this saturation, but they require a very intense pump power for too short a time to use the FIR radiation in high sensitive experiments with heterodyne detection. This is the case, for instance, of RFWM. In this work we describe the experimental conditions to achieve a high efficiency 90 micron Raman conversion in ammonia, with both short and long pulses.