Antici P, Chen S N, Gremillet L, Grismayer T, Mora P, Audebert P, Fuchs J
Istituto Nazionale di Fisica Nucleare, Via E. Fermi, Frascati 40-00044, Italy.
Rev Sci Instrum. 2010 Nov;81(11):113302. doi: 10.1063/1.3499250.
A technique developed to measure in time and space the dynamics of the electron populations resulting from the irradiation of thin solids by ultraintense lasers is presented. It is a phase reflectometry technique that uses an optical probe beam reflecting off the target rear surface. The phase of the probe beam is sensitive to both laser-produced fast electrons of low-density streaming into vacuum and warm solid density electrons that are heated by the fast electrons. A time and space resolved interferometer allows to recover the phase of the probe beam sampling the target. The entire diagnostic is computationally modeled by calculating the probe beam phase when propagating through plasma density profiles originating from numerical calculations of plasma expansion. Matching the modeling to the experimental measurements allows retrieving the initial electron density and temperature of both populations locally at the target surface with very high temporal and spatial resolution (~4 ps, 6 μm). Limitations and approximations of the diagnostic are discussed and analyzed.
本文介绍了一种用于在时间和空间上测量超短脉冲激光辐照薄固体产生的电子群体动力学的技术。这是一种相位反射测量技术，它使用从靶后表面反射的光学探测光束。探测光束的相位对流入真空中的低密度激光产生的快电子和被快电子加热的温暖固体密度电子都很敏感。一个时间和空间分辨干涉仪可以恢复探测光束在靶上采样的相位。通过计算探测光束在穿过由等离子体膨胀的数值计算产生的等离子体密度分布时的相位，对整个诊断进行了计算建模。将建模与实验测量相匹配，可以在靶表面以非常高的时间和空间分辨率（~4 ps，6 μm）局部检索这两个群体的初始电子密度和温度。讨论并分析了该诊断方法的局限性和近似性。
