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Theoretical studies of Raman Scattering and Chirped Pulse Amplification in Plasma

等离子体拉曼散射和啁啾脉冲放大的理论研究

基本信息

批准号：
EP/D052599/1
负责人：
Dino Anthony Jaroszynski
金额：
$ 40.75万
依托单位：
University of Strathclyde
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FD052599%2F1
关键词：
Theoretical studies Raman Scattering Chirped

项目摘要

The proposal is to explore the potential of using a fully ionised gas or plasma as an efficient short pulse amplifier. By exciting a plasma wave by two colliding (seed and pump respectively) pulses in plasma, it is possible to amplify the short seed pulse efficiently. The bandwidth of the plasma amplifier medium is enhanced when a chirped pump pulse is utilised. In the linear regime, before saturation of the amplifying process takes over, the long chirped pump laser pulse provides distributed amplification where different spectral components of the seed are amplified at different longitudinal positions in the plasma through the creation of a chirped plasma density echelon, much like a diffraction grating. This behaves as a long chirped mirror which simultaneously backscatters and compresses the chirped pump pulse and effectively broadens the gain bandwidth to that of the pump. The gain and the bandwidth of the amplifier depend on the natural oscillation frequency of the plasma (the plasma frequency) and the chirp rate (the rate at which the frequency changes along the pump pulse) and spectral bandwidth of the pump. This contrasts with conventional chirped pulse amplifiers (CPAs) and optical parametric chirped pulse amplifiers (OPCPAs) where the probe is chirped while the pump is usually monochromatic (un-chirped). The chirped pulse Raman amplifier has potential use either as a high fidelity ultra-short pulse high power linear amplifier or as a compressor of high energy chirped pulses from a conventional CPA amplifier. It also avoids the requirement for extremely large and expensive optical elements and compressors in vast vacuum chambers. Furthermore, because chirped pulse Raman amplification is a three wave parametric interaction it provides a means of eliminating pre-pulses and pedestals which usually limit the usefulness of conventional solid state CPA amplifiers. This research proposal will investigate the linear and non-linear stages of Raman amplification with a view to develop extremely high power lasers which have the potential of opening up new frontiers of physics such as using lasers to create particles from vacuum or create astrophysical conditions in the laboratory.

该建议是探索使用完全电离的气体或等离子体作为有效的短脉冲放大器的潜力。通过由等离子体中的两个碰撞（分别为种子脉冲和泵浦脉冲）脉冲激发等离子体波，可以有效地放大短种子脉冲。当利用啁啾泵浦脉冲时，等离子体放大器介质的带宽增强。在线性状态中，在放大过程的饱和接管之前，长啁啾泵浦激光脉冲提供分布式放大，其中种子的不同光谱分量通过创建啁啾等离子体密度梯队（chirped plasma density echelon）在等离子体中的不同纵向位置处被放大，非常像衍射光栅。这表现为长啁啾镜，其同时反向散射和压缩啁啾泵浦脉冲，并且有效地将增益带宽加宽到泵浦的增益带宽。放大器的增益和带宽取决于等离子体的自然振荡频率（等离子体频率）和啁啾率（频率沿着泵浦脉冲变化的速率）以及泵浦的光谱带宽。这与传统的啁啾脉冲放大器（CPA）和光参量啁啾脉冲放大器（OPCPA）形成对比，在传统的CPA和OPCPA中，探针是啁啾的，而泵浦通常是单色的（非啁啾的）。啁啾脉冲拉曼放大器既可以作为高保真超短脉冲高功率线性放大器，也可以作为传统CPA放大器的高能啁啾脉冲压缩器。它还避免了在巨大的真空室中需要非常大和昂贵的光学元件和压缩机。此外，由于啁啾脉冲拉曼放大是三波参量相互作用，因此它提供了一种消除通常限制常规固态CPA放大器的有用性的预脉冲和寄生脉冲的手段。这项研究建议将研究拉曼放大的线性和非线性阶段，以期开发极高功率的激光器，这些激光器有可能开辟物理学的新领域，例如利用激光从真空中产生粒子或在实验室中创造天体物理条件。