激光作用下纳米限域介质材料中的电子加速过程

采用蒙特卡罗方法模拟了1064 nm,GW/cm²级脉冲激光辐照下,纳米尺度材料中电子迁移及加速过程.电子在激光场中迁移的过程涉及晶格散射、表面散射以及碰撞电离等作用.结果表明:材料的尺度小到一定程度后,表面散射作用主导电子散射过程,小尺寸限制效应表现明显,电子很难有效地吸收激光能量.研究结果对分析具有纳米尺度微结构材料的激光损伤行为提供了依据.同时,根据该小尺寸限制效应可以设计出具有新型纳米微结构的高激光损伤阈值薄膜. 关键词： 激光辐照 小尺度效应 电子加速 蒙特卡罗模拟

The laser induced electronic acceleration process in nanostructured dielectric

The Monte Carlo method has been used to simulate the process of electron transport and acceleration in a nano-dimensional unit when irradiated by laser pulse of wavelength 1064 nm and power density of GW/cm² level. When electrons transport in laser field, the scattering of electron-phonon and electron-surface are considered. The results show that: when the size of simulation unit is small to a degree, electron-surface scattering will dominate the scattering process and the small size effect becomes obvious. As a result, the electron is difficult to absorb laser energy. Based on the results, we can design new kind of films with nanostructure and improve the laser induced damage threshold of optical films.