研究微微秒变象管相机用的超短激光脉冲

本文概述了研制微微秒变像管相机对超短激光脉冲的形状、持续时间、脉冲形状内的能量分布、光谱成份等的要求。指出:矩形激光脉冲是检验微微秒变像管相机空间分辨率和时间分辨率最满意的脉冲及理想的光源。 利用被动锁模,自孔径选模,适当选择脉冲氙灯放电的网络参数,使在一定的时间内产生线性增加的增益系数α,确定在非线性位相过程开始产生的净增益⊿α,控制激光脉冲通过染料的次数m,维持腔内总振荡光子数N在激光阈值以上的增益曲线内不变,控制反转粒子数,使光脉冲前后沿每次得到相同的抽数,从而脉冲前后沿有相同的增益。由这种运转的激光输     

用脉冲激励激光产生微微秒光脉冲

脉冲激励产生的微微秒光脉冲的峰值功率,和连续激励时比较,具有很大的优点,对研究光和物质的相互作用极为重要。采用脉冲激励时,特别是对固体激光器,通常采用把放大介质和可饱和染料配合在一起,在Q开关的同时进行模同步的方法。超短光脉冲产生机理的实时处理法是精确而又方便的。利用脉冲激励来获得超短光脉冲时存在的最大问题是振荡的稳定性(重复性)。因此,本文介绍一下用可饱和染料产生稳定的微微秒光脉冲及得到脉宽可变的激光的     

用连续激励激光产生微微秒光脉冲

用连续激励激光所得的微微秒光脉冲的峰值输出,至多约为10~2瓦,这和脉冲激励相比非常小。可是,它可在任意时间内,保持峰值输出和脉宽波动小的光脉冲群,所以,光脉冲群能量的长时间平均值,当然是一般连续激励的激光较大。因此,连续激励激光所得的微微秒光脉冲,适用于脉码调制光通信及测定由取样信号积分法产生的线性高速度现象等方面。要得到脉宽窄的光脉冲,适     

微微秒光脉冲的测量

由于以锁模为首的激光脉冲技术的进展，现在已能容易地得到从微微秒(10^-12秒) 到亚微微秒(10^-13秒)的宽度极短的光脉冲。这种超短光脉冲，对于以很高的时间分辨率阐明光和物质的相互作用是非常有用的，同时也被用于单模光纤的大容量光通信、高精度激光雷达以及激光核聚变的研究。对于涉及这许多方面的微微秒光脉冲的应用研究，欲要定量地估价所得的研究结果，微微秒领域的光脉冲的计测将成为不可缺少的基本技术。     

微微秒光脉冲的测量方法

测量几微微秒的光脉冲(以下简称光脉冲)和由它激励所辐射物质产生的响应光脉冲(以下简称二次光),分两类:即测量比脉宽长得多的时间积分物理量和测量微微秒级的时间变化量。前者包括:测量总输出能量,利用宽带示波器观测模同步脉冲群(不是测量单位脉冲强度,而是测量能量),以及测量光谱等。而且,仍旧采用电子装置和分光器等原有的方法。后者包括:测量波形和测量时间分辨光谱等。目前,正积极从事研究这方面的特殊的观测方法。测量波形采用三种方法:1)实时测量     

用全息术记录飞行中的微微秒光脉冲

一种利用脉冲激光使全息图曝光的新技术最近已能对迅速通过空间的脉冲波前进行全息记录。这种最新水平的新技术可能应用于光学过程的研究,如光纤色散、不用电子学技术的脉冲宽度的测量以及诸如激光热核聚变中氘靶聚爆的多种超快过程的研究。     

微微秒光脉冲的测量

微微秒光脉冲技术的发展极为迅速,目前已能获得10~(-12)～10~(-14)s的激光脉冲。在进行超短光脉冲的产生和应用方面的研究时,对脉宽的定量计测无疑是极端重要的。测量方法大致有间接测量法、相关测量法和直接测量法。     

微微秒光脉冲宽度测量

在微微秒光谱实验中,光脉冲时间宽度测量是比较重要的参数。测量手段主要有:自相关技术,双光子荧光法及条纹照像法等。我们利用自相关技术,对微微秒激光系统,进行超短脉冲宽度的测量。自相关器分辨率比较高,能分辨到0.5ps,虽然自相关技术发展比较早,但实际测量中仍然存在技术和方法的问题。本文主要介绍实验测量和自相关原理。     

用可饱和吸收获得70毫微微秒的脉冲

据罗切斯特大学的一个小组报导，他们获得了可能是迄今为止最短的激光脉冲。该大学激光力能学实验室的莫罗(G. Mourou)和赛泽第二（T. Sizer II)已经产生出短于70毫微微秒(7×10^-14秒)的激光脉冲。但是在如此短暂的时间尺度上，测量设备不很准确，研究者认为，事实上脉冲可能还要短些。     

测量微微秒光脉冲的新技术

美帝贝耳电话实验室最近发明了一种新技术,可以准确地测量持续时间约为10^-12秒的单色激光脉冲。这一进步使得观察诸如在原子和分子中发生的微微秒过程成为可能。它也为可能的激光通讯系统提供了一种新的脉冲译码方法。     

CW autocorrelation measurements of picosecond laser pulses

Completely general and novel expressions are presented fornth-order fast or slow correlation functions, with or without background contributions, from which more specializednth- and second-order auto-correlation functions are derived. A straightforward method for obtaining CW autocorrelation measurements of picosecond pulses is then described which employs an audio loudspeaker driven at 30 Hz in one arm of the correlator to permit autocorrelation display at this frequency. Results of the application of this device to measurements of the picosecond pulses from a CW synchronously mode-locked Rhodamine 6G dye laser are presented.     

Experimental study of single picosecond light pulses

Single picosecond light pulses from a mode-locked Nd:glass laser are investigated by several methods. Their temporal structure is studied by two-photon fluorescence. The frequency spectra are measured quantitatively. The energy distribution is simultaneously investigated by three-photon fluorescence, photoelectric measurements, and quantitative studies of the contrast ratio of the two-photon fluorescence. The pulse shape is measured using a method based on the stimulated Raman effect. It is observed that the pulses are weakly asymmetric-the pulse decay is slower (exponential) than the pulse rise (Gaussian). Bandwidth-limited pulses of 4-8 ps are present in the leading part of the pulse train. Substantial frequency broadening develops as the pulse train reaches its maximum and a subpicosecond structure is formed in the trailing part of the pulse train.     

Tunable near-infrared picosecond pulses from a short-cavity dye laser

We report on the generation of tunable infrared picosecond pulses by a short-cavity dye laser system consisting of a short cavity, a three-stage amplifier, and a wavelength control unit. The laser emission is temporally, spectrally, and spatially resolved. The conditions for optimum performance are ascertained, and the output characteristics important to experimental applications are determined.     

激光等离子体诊断用微微秒紫外高功率激光脉冲的产生

氙灯泵浦的可调谐染料激光器锁模脉冲用XeCl准分子激光器泵浦的三级染料激光放大器放大后,经倍频再用XeCl准分子激光器放大,在308毫微米处获得了微微秒高功率激光脉冲输出,其峰值功率可达500兆瓦,功率净增益为200。     

Semiconductor laser output modulated in GHz frequency region observed by image tube streak camera

The image tube streak camera was applied to the observation of fast modulated continuous light signals. Intensity modulation of a semiconductor laser was observed up to 5 GHz.     

用皮秒激光产生宽度可调的高压电脉冲

本文报道用两个具有可变相对延时的皮秒激光脉冲,先后驱动两个光电子开关,产生前后沿均为亚毫微秒的宽度可调高压电脉冲。     

Generation of 10 nJ picosecond pulses from a modelocked fibre laser

Wavelength-tunable very high power soliton fibre lasers are constructed using chirped fibre Bragg gratings. Near-bandwidth limited pulses with widths of 4.0 ps and pulse energies up to 10 nJ are generated directly from passively modelocked erbium fibre lasers. A stable pulse repetition rate of 17 MHz is obtained, giving rise to an average modelocked output power of 170 mW     

Generation and kilohertz rate amplification of synchronizedfemtosecond and picosecond laser pulses

Synchronized femtosecond and tunable picosecond laser pulses have been generated using a linear cavity configuration in both lasers. The long-term stability of the synchronization, as well as the frequency of the synchronously pumped femtosecond dye laser, is assured by active stabilization of the cavity length. Additionally, the picosecond and femtosecond pulses have been amplified in dual amplifier chains to pulse energies in the microjoule range at a 1 kHz repetition rate. The total peak intensity available for two-photon, nonlinear excitations is on the order of 10⁹ times greater than that available from unamplified beams