论文标题
映射来自激光 - 血压相互作用的高谐波光谱的幂律衰减
Mapping the power-law decay of high-harmonic spectra from laser-plasma interactions
论文作者
论文摘要
当激光照射一个固体等离子体靶标时，可以通过相对论的高阶谐波生成过程来操纵可见或近红外光，以产生相干极端紫外线（XUV）或X射线。反射信号的光谱成分的强度随着谐波顺序的增加而衰减，并且这种非线性过程的效率在很大程度上取决于该衰减的迅速性。这受激光 - 血浆相互作用的条件，为已提出了各种模型。在相对论强度上，通常会说出表现出具有8/3或4/3的幂律衰减的频谱。在这里，我们分析了该指数对相互作用参数的依赖性，包括入射角，载体包络阶段，激光的强度和前等离子体长度，并讨论优化的机会。我们的仿真表明，光谱衰减不是一个通用指数，而是激光 - 血压相互作用参数的连续函数。
Visible or near infra-red light can be manipulated to produce bursts of coherent extreme ultraviolet (XUV) or X-rays via the relativistic high-order harmonic generation process when a laser irradiates a solid plasma target. The intensity of the spectral components of the reflected signal decays with increase of harmonic order and the efficiency of this non-linear process largely hinges on how prompt this decay is. This is governed by the conditions of the laser-plasma interaction for which various models have been proposed. At relativistic intensities, a spectrum exhibiting a power-law decay with an exponent of 8/3 or 4/3 is often stated. Here, we analyse the dependence of this exponent on interaction parameters including the angle of incidence, the carrier envelope phase, intensity of the laser and the pre-plasma length, and discuss opportunities for optimization. Our simulations show that, rather than there being one universal exponent, the spectral decay is a continuous function of the laser-plasma interaction parameters.
