Pump laser for TW laser system

用于 TW 激光系统的泵浦激光器

• 批准号: ST/X004716/1
• 负责人: Simon Martin Hooker
• 金额: $ 10.2万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FX004716%2F1
• 关键词: Pump; laser; TW; system

The John Adams Institute (JAI) is a centre of excellence for advanced accelerator science and technology, based at the University of Oxford, Royal Holloway University of London, and Imperial College London. An important theme within JAI's research is the development of advanced plasma accelerators. These exploit the huge electric fields developed within density waves driven by intense laser pulses (or particle bunches) as they propagate through plasma. Laser-driven plasma accelerators have generated electron bunches with energies equivalent to that obtained by accelerating them across nearly 10 billion volts in plasma accelerator stages only a few centimetres long. Plasma accelerators therefore offer the potential to drive compact sources of energetic particles, and by oscillating these particles with magnetic fields -- as is done in today's, stadium-sized synchrotron facilities -- they could generate very bright X-ray sources for use in science, medicine, and industry. In the longer term, plasma accelerators could be used in a new generation of high energy particle colliders.The JAI programme on Laser Wakefield Accelerators (LWFAs) aims to tackle many of the key issues which need to be solved before their many promising applications can be realized. In Oxford, this work concentrates on developing an architecture for enabling high-energy plasma accelerators operating at high (kilohertz) repetition rates. The first component of this architecture is the hydrodynamic optically-field-ionized (HOFI) plasma channel, which was developed at Oxford. These are free-standing, "indestructible" optical waveguides capable of channelling relativistically-intense laser pulses over metre-scale distances. As such, they are a key technology for providing the plasma "target" in future high-repetition-rate laser-plasma accelerators.The second component is the multi-pulse LWFA (MP-LWFA) concept, also developed in Oxford. This new approach seeks to overcome a fundamental road-block in the application of LWFAs: the short pulse (less than one-ten-billionth of a second), high-energy (a few joules) Ti:sapphire lasers used today have very low wall-plug efficiency (< 0.1%), and are limited to operation at repetition rates of only a few pulses per second. In contrast, many near- or medium-term applications of LWFAs require the delivery of thousands of pulses per second; and longer-term applications, such as particle colliders, also require much higher wall-plug efficiency.The essential idea of MP-LWFA is to drive the plasma wave with a train of low energy laser pulses, rather than with a single, high-energy pulse. Each pulse in the train excites a low amplitude plasma wave, and if the pulses are spaced by the wavelength of the plasma wave, then the plasma waves add coherently, causing the amplitude of the plasma wave to grow towards the back of the train. This new approach opens up LWFAs to novel, efficient laser technologies which cannot generate short pulses directly, but which can provide longer, high-energy pulses at high (kilohertz) repetition rates. The current proposal comprises a request funds to replace a pump laser which lies at the heart of the terawatt laser system used extensively in the JAI plasma accelerator research programme. This pump laser is nearly 20 years old and the manufacturer will no longer service or repair it. If it were to fail we could not complete a large fraction of our research programme.

约翰亚当斯研究所（JAI）是一个先进加速器科学和技术的卓越中心，位于牛津大学，皇家霍洛威伦敦大学和帝国理工学院伦敦。JAI研究的一个重要主题是开发先进的等离子体加速器。这些技术利用了强激光脉冲（或粒子束）在等离子体中传播时，在密度波中产生的巨大电场。激光驱动的等离子体加速器产生的电子束，其能量相当于在只有几厘米长的等离子体加速器级中将它们加速超过近100亿伏所获得的能量。因此，等离子体加速器提供了驱动高能粒子的紧凑源的潜力，并且通过用磁场振荡这些粒子-就像在今天的体育场大小的同步加速器设施中所做的那样-它们可以产生非常明亮的X射线源，用于科学，医学和工业。从长远来看，等离子体加速器可用于新一代的高能粒子对撞机。日本原子能研究院的激光韦克菲尔德加速器方案旨在解决在实现其许多有前途的应用之前需要解决的许多关键问题。在牛津大学，这项工作集中在开发一种架构，使高能等离子体加速器在高（千赫）重复率下运行。这种结构的第一个组成部分是流体动力学光场电离（HOFI）等离子体通道，这是在牛津大学开发的。这些是独立的，“坚不可摧”的光波导，能够在米级距离上传输相对论强度的激光脉冲。因此，它们是未来高重复率激光等离子体加速器中提供等离子体“靶”的关键技术。第二个组成部分是多脉冲LWFA（MP-LWFA）概念，也是在牛津大学开发的。这种新方法试图克服LWFAs应用中的一个基本障碍：目前使用的短脉冲（小于百亿分之一秒）、高能（几焦耳）钛宝石激光器具有非常低的壁插效率（< 0.1%），并且仅限于每秒几个脉冲的重复率。相比之下，LWFA的许多短期或中期应用需要每秒传输数千个脉冲;而长期应用，如粒子对撞机，也需要更高的壁插效率。MP-LWFA的基本思想是用一系列低能激光脉冲驱动等离子体波，而不是用单个高能脉冲。序列中的每个脉冲激发低振幅等离子体波，并且如果脉冲由等离子体波的波长间隔开，则等离子体波相干地相加，导致等离子体波的振幅朝向序列的后部增长。这种新方法为LWFAs开辟了新的，高效的激光技术，这些技术不能直接产生短脉冲，但可以以高（千赫）重复率提供更长的高能脉冲。目前的提案包括一项请求资金，以取代泵浦激光器，该激光器是JAI等离子体加速器研究计划中广泛使用的太瓦激光系统的核心。这台泵浦激光器已经用了将近20年了，制造商将不再维修它。如果它出了故障，我们就无法完成大部分的研究计划。