飞秒掠入射X射线散射观测固体在高强度laser辐照下的纳米尺度次表面动力学
Nanoscale subsurface dynamics of solids upon high-intensity laser irradiation observed by femtosecond grazing-incidence x-ray scattering
摘要：
观察超快激光引起的纳米尺度系统的结构变化对于理解强烈的光-物质相互作用的动力学是必不可少的。对于$10^{14} \, \rm W/cm^2$量级的激光强度，在表面处和表面下方产生高度碰撞的等离子体。随后的传输过程，如热传导，电子离子热化，表面烧蚀和再固化发生在皮秒和纳秒的时间尺度。成像方法，例如使用X射线自由电子激光（XFEL），迄今无法测量具有适当时间和空间分辨率的激光-固体相互作用的深度分辨次表面动态。在这里，我们展示了皮秒掠入射小角度X射线散射（GISAXS）从激光产生的等离子体使用XFEL脉冲。使用多层（ML）样品，表面烧蚀和亚表面密度动态测量与纳米深度分辨率。我们的实验数据挑战了极端条件下最先进的物质建模，并为激光材料加工和高能量密度科学开辟了新的前景。
英文摘要：
Observing ultrafast laser-induced structural changes in nanoscale systems is essential for understanding the dynamics of intense light-matter interactions. For laser intensities on the order of $10^{14} \, \rm W/cm^2$, highly-collisional plasmas are generated at and below the surface. Subsequent transport processes such as heat conduction, electron-ion thermalization, surface ablation and resolidification occur at picosecond and nanosecond time scales. Imaging methods, e.g. using x-ray free-electron lasers (XFEL), were hitherto unable to measure the depth-resolved subsurface dynamics of laser-solid interactions with appropriate temporal and spatial resolution. Here we demonstrate picosecond grazing-incidence small-angle x-ray scattering (GISAXS) from laser-produced plasmas using XFEL pulses. Using multi-layer (ML) samples, both the surface ablation and subsurface density dynamics are measured with nanometer depth resolution. Our experimental data challenges the state-of-the-art modeling of matter under extreme conditions and opens new perspectives for laser material processing and high-energy-density science.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
