In order to study the charge characteristics of monocrystalline silicon irradiated by femtosecond pulsed laser, measurement systems of charge and infrared temperature induced by femtosecond pulse laser irradiation monocrystalline silicon are established by using oscilloscope and infrared thermal imager. The monocrystalline silicon (circle disc) irradiated by femtosecond pulse laser are carried out along the thickness direction of monocrystalline silicon. The experimental results show that the thermo-mechanical coupling effect of femtosecond pulsed laser irradiated on monocrystalline silicon will produce polarization in the target. At the initial stage of laser irradiation, the laser damage threshold of the interface between crystal surface and air is low and the charge mainly transfers along the surface of monocrystalline silicon, resulting in a high polarization. With the continuation of laser irradiation, it proves that the charge transfers in monocrystalline silicon gradually, and the polarization degree decreases with the modification of the material internal structure. After laser irradiation for a certain time, the charge transfers tend to be stable. Because the target lies in front of the laser focus, its energy density is insufficient to destroy the macrostructure of the target due to laser-pressure and temperature gradient, the polarization effect tends to be stable, resulting in a stable periodic change of charge transfer and recovery.

中文翻译：

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激光辐照单晶硅电荷转移特性研究

为了研究飞秒脉冲激光辐照单晶硅的电荷特性，利用示波器和红外热像仪建立了飞秒脉冲激光辐照单晶硅的电荷和红外温度测量系统。飞秒脉冲激光照射的单晶硅（圆盘）沿单晶硅的厚度方向进行。实验结果表明，飞秒脉冲激光照射在单晶硅上的热机械耦合效应会在靶材中产生偏振。在激光照射初期，晶体表面与空气界面的激光损伤阈值较低，电荷主要沿单晶硅表面转移，导致高极化。随着激光照射的继续，证明单晶硅中的电荷逐渐转移，极化程度随着材料内部结构的改变而降低。激光照射一定时间后，电荷转移趋于稳定。由于目标位于激光焦点前方，由于激光压力和温度梯度，其能量密度不足以破坏目标的宏观结构，极化效应趋于稳定，导致电荷转移和恢复。激光照射一定时间后，电荷转移趋于稳定。由于目标位于激光焦点前方，由于激光压力和温度梯度，其能量密度不足以破坏目标的宏观结构，极化效应趋于稳定，导致电荷转移和恢复。激光照射一定时间后，电荷转移趋于稳定。由于目标位于激光焦点前方，由于激光压力和温度梯度，其能量密度不足以破坏目标的宏观结构，极化效应趋于稳定，导致电荷转移和恢复。