面向高增益聚变的激光驱动器技术探索昆吾低相干宽带激光装置

Exploration of laser driver technology for high-gain fusion: the Kunwu low-coherence broadband laser facility

  • 摘要: 抑制激光等离子体不稳定性是实现高增益激光惯性约束聚变的关键因素之一。降低激光的相干性,打破激光等离子体相互作用过程的增长路径与时间,有望实现激光等离子体不稳定性的更好抑制。本文综述了低相干宽带激光驱动器的技术进展,包括时间、光谱精密整形的低相干前端,低相干宽带脉冲的高效放大、频率转换及束匀滑技术。通过上述创新技术的集成应用,建成了昆吾低相干宽带激光装置,并进一步将其打造成为面向未来高增益聚变研究的激光技术和聚变物理的创新研发平台,已开展系列激光技术及激光等离子体相互作用的创新原理、技术及实验研究,并取得了若干创新成果。

     

    Abstract: Suppression of laser plasma instabilities is one of the key factors to achieve high-gain laser inertial confinement fusion. Reducing laser coherence and breaking the growth path and time of laser-plasma interaction process are expected to achieve better suppression of laser-plasma instability. Low coherence pulses with randomly distributed spectral phases have the characteristics of instantaneous broadband and good spatial coherence. As the driving pulses, combined with beam smoothing techniques, low coherence speckle distribution in the dimensions of temporal, spatial, and polarization can be achieved. Shanghai Institute of Laser Plasma (SILP) has conducted research on low coherence laser driver technology based on the neodymium glass level amplification technology route. This study aims to review the developments, including low-coherence front-end with precise time and spectral shaping, high-efficiency amplification, frequency conversion and beam smoothing of low-coherence broadband pulses. Through the integrated application of the aforementioned innovative technologies, the Kunwu low-coherence broadband laser device has been built, which can deliver kilojoules pulse with a bandwidth of 13 nm. At present, a series of laser-plasma interaction experiments have been carried out, confirming the inhibitory effect of broadband laser on stimulated Raman scattering and stimulated Brillouin scattering, and providing important support for high-gain laser inertial confinement fusion research.

     

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