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参量自注入放大产生皮秒中红外脉冲 总被引:1,自引:0,他引:1
首次采用参量自注入放大方法产生了皮秒中红外超短脉冲.该方法的优点是仅使用1块红外非线性晶体,实验装置简单,成本低.入射光源是锁模皮秒Nd:YAG激光器,用来泵浦AgGaS2单晶,经过参量过程辐射3—10μm的皮秒脉冲激光.最大红外脉冲激光输出能量为14μJ. 相似文献
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中红外激光具有多种优势,可以广泛地用到生物、化学、物理等科学研究领域。通常采用直接激射和非线性频率转换这两种方式产生中红外激光,然而,为了实现中红外宽带超短脉冲的发射,非线性频率下转换是现今的唯一方法。脉冲内差频(IP-DFG)是一种简单的非线性频率转换方法,文中对红外IP-DFG的工作做了详细的回顾,从中红外激光晶体和基于IP-DFG产生具有超宽带的中红外超短脉冲的先进工作两个方面做了综述和评论,分别比较了非线性晶体类型、驱动脉冲源、产生超宽带中红外脉冲的光谱范围、转化效率等,并在最后讨论和阐明了IP-DFG领域面临的机遇和挑战。 相似文献
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真空紫外超短脉冲激光具有波长短、单光子能量高、脉宽小等特点,在飞秒化学以及超快动力学等方面具有相当广泛的应用前景.由于直接利用受激辐射获得真空紫外超短脉冲是相当困难,因此利用非线性频率转换技术,超短脉冲与惰性气体相互作用,将红外、可见或紫外光波段的超短脉冲转换到真空紫外波段是目前获得紫外超短脉冲最快捷有效的方式.围绕真空紫外超短脉冲的产生及其在超短动力学中应用展开,介绍了产生真空紫外超短脉冲的高斯谐波、空心光纤四波混频和光丝四波混频的方法,对其优缺点作了评述,并对真空紫外超短脉冲激光在超快动力学过程中的应用进行了简单的总结. 相似文献
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中红外超短脉冲的产生及其研究的最新进展 总被引:4,自引:0,他引:4
中红外超短(皮秒至飞秒量级)脉冲是研究固体、表面、等离子体和光化学等领域里各种瞬态过程的有力工具。着重介绍了常用的四种产生中红外超短脉冲的方法,即光学自由感应衰减、半导体开关、光学参量振荡以及差频产生,并比较了它们的优缺点,概述了这方面研究的最新进展及其应用。 相似文献
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超短光脉冲的概念、产生和应用 总被引:1,自引:0,他引:1
激光的重要特征之一是可以产生纯电子学所不能产生的超短脉冲.自从激光诞生以来,超短光脉冲的产生、控制及其应用获得了飞速的发展.本文就超短光脉冲的概念、产生方法及其多领域的应用作一介绍. 相似文献
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简要介绍一台环形腔飞秒超短脉冲激光器,给出了有关结构参数及实验结果,并对实验研究中的一些现象进行了讨论。 相似文献
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Lihuang Lin Bing Xu Xiaodong Yang Chuandong LiBin Ouyang Runwen Wang 《Chinese Journal of Lasers》1993,2(4):295-298
A Ti: sapphire laser pumped synchronously by a bounded frequency-doubled pulse train of a pulsed mode-locked Nd : YAG laser was presented. The temporal characteristics of the laser and optimal conditions of generating stable ultrashort pulses are also given. 相似文献
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应用傅里叶频谱分析法,给出了光栅在啁啾超短脉冲光波照射下菲涅耳衍射方程并分析了其Talbot效应. 数值计算表明,在Talbot距离处的衍射光强不仅与照射的超短脉冲光波的宽度有关,而且与脉冲光波的啁啾有关. 根据光栅在Talbot距离处衍射光强的变化,给出了一种检验超短脉冲光波是否含有啁啾的简单方法.
关键词:
光栅
菲涅耳衍射
Talbot效应
啁啾超短脉冲激光 相似文献
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Jonghee Yoon Junseong Park Myunghwan Choi Won Jong Choi Chulhee Choi 《Annalen der Physik》2013,525(3):205-214
Absorption of photon energy by cells or tissue can evoke photothermal, photomechanical, and photochemical effects, depending on the density of the deposited energy. Photochemical effects require a low energy density and can be used for reversible modulation of biological functions. Ultrashort‐pulsed lasers have a high intensity due to the short pulse duration, despite its low average energy. Through nonlinear absorption, these lasers can deliver very high peak energy into the submicrometer focus area without causing collateral damage. Absorbed energy delivered by ultrashort‐pulsed laser irradiation induces free electrons, which can be readily converted to reactive oxygen species (ROS) and related free radicals in the localized region. Free radicals are best known to induce irreversible biological effects via oxidative modification; however, they have also been proposed to modulate biological functions by releasing calcium ions from intracellular organelles. Calcium can evoke variable biological effects in both excitable and nonexcitable cell types. Controlled stimulation by ultrashort laser pulses generate intracellular calcium waves that can modulate many biological functions, such as cardiomyocyte beat rate, muscle contractility, and blood–brain barrier (BBB) permeability. This article presents optical methods that are useful therapeutic and research tools in the biomedical field and discuss the possible mechanisms responsible for biological modulation by ultrashort‐pulsed lasers, especially femtosecond‐pulsed lasers. 相似文献
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Films of magnetic nanoparticles uniformly mixed with non-magnetic nanoparticles have been produced by ultrashort pulsed laser deposition. These films present innovative characteristics with respect to their counterparts produced by standard techniques, as for example nanosecond laser ablation or sputtering, due to the peculiar shape and preferential distribution of their constituent nanoparticles. In the present investigation, the difficult coalescence among the deposited nanoparticles, specific characteristic of the ultrashort pulsed laser deposition, is particularly stressed for what concerns its effect on the collective magnetic behaviour. In particular, we observed that, even for a significant fraction of magnetic particles, the films exhibit an unusual high remanent magnetization, together with relatively low values of saturation and coercive fields, showing a strong squareness of the hysteresis loops. In perspective, these nanogranular films appear very promising for potential application as permanent magnets and in magnetic recording. 相似文献
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为研究多物理参数(耦合系数、电子热导率、电子热容、晶格热容)同时随温度变化对短脉冲激光辐照金属材料产生温度场分布的影响,基于双温耦合理论,建立了短脉冲激光辐照金属材料金的加热过程的有限元求解模型。在同时考虑脉冲激光的空间、时间分布和多参数同时随温度变化的情况下,得到短脉冲激光辐照金属材料金激励产生的温度场二维瞬态分布,并进一步比较了多物理参数同时随温度变化和采用室温物理参数两种情况下温度场分布的区别。数值结果表明:多物理参数同时随温度变化使电子温度和晶格温度的上升变快,最大值变大,而且使得材料中激光穿透直接辐照到的区域温度变高。 相似文献
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理论上研究了超短脉冲激光照射下光栅的Talbot效应,得到了超短脉冲激光照射下光栅Talbot图像的性质.实验上采用严格的实验方法(频率分辨光学开关装置测量超短脉冲激光、反射式扩束系统对超短脉冲进行扩束)很好地验证了理论分析结果.理论分析和实验结果表明,超短脉冲激光照射下光栅的Talbot图像的对比度会显著下降,而且超短脉冲激光的脉宽越短,Talbot距离越大,Talbot图像的对比度会进一步下降. 相似文献
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Trends in ultrashort and ultrahigh power laser pulses based on optical parametric chirped pulse amplification
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Since the proof-of-principle demonstration of optical parametric amplification to efficiently amplify chirped laser pulses in 1992,optical parametric chirped pulse amplification(OPCPA)became the most promising method for the amplification of broadband optical pulses.In the meantime,we are witnessing an exciting progress in the development of powerful and ultrashort pulse laser systems that employ chirped pulse parametric amplifiers.The output power and pulse duration of these systems have ranged from a few gigawatts to hundreds of terawatts with a potential of tens of petawatts power level.Meanwhile,the output pulse duration based on optical parametric amplification has entered the range of fewoptical-cycle field.In this paper,we overview the basic principles,trends in development,and current state of the ultrashort and laser systems based on OPCPA,respectively. 相似文献