Turnbull D, Bucht S, Davies A, Haberberger D, Kessler T, Shaw J L, Froula D H
University of Rochester Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623, USA.
University of Rochester Department of Physics and Astronomy, Bausch and Lomb Hall, Rochester, New York 14627, USA.
Phys Rev Lett. 2018 Jan 12;120(2):024801. doi: 10.1103/PhysRevLett.120.024801.
We propose a new laser amplifier scheme utilizing stimulated Raman scattering in plasma in conjunction with a "flying focus"-a chromatic focusing system combined with a chirped pump beam that provides spatiotemporal control over the pump's focal spot. Pump intensity isosurfaces are made to propagate at v=-c so as to be in sync with the injected counterpropagating seed pulse. By setting the pump intensity in the interaction region to be just above the ionization threshold of the background gas, an ionization wave is produced that travels at a fixed distance ahead of the seed. Simulations show that this will make it possible to optimize the plasma temperature and mitigate many of the issues that are known to have impacted previous Raman amplification experiments, in particular, the growth of precursors.
我们提出了一种新的激光放大器方案，该方案利用等离子体中的受激拉曼散射，并结合“飞行焦点”——一种与啁啾泵浦光束相结合的色散聚焦系统，可对泵浦光斑进行时空控制。使泵浦强度等值面以v=-c的速度传播，以便与注入的反向传播种子脉冲同步。通过将相互作用区域中的泵浦强度设置为略高于背景气体的电离阈值，会产生一个电离波，该电离波在种子前方固定距离处传播。模拟结果表明，这将有可能优化等离子体温度，并减轻许多已知影响先前拉曼放大实验的问题，特别是前驱体的增长问题。
