Q开关激光束在材料中产生冲击波的物理机理研究

以Q开关红宝石脉冲激光瞬态加热压电陶瓷表面上的银膜,研究了激光在吸收材料中产生冲击波的物理机理。分析所产生的电信号表明,激光产生冲击波的物理机理有两类:一是热冲击,它起源于弹性样品表层快速吸收激光脉冲能量所造成的热膨胀和巨大的应力梯度;另一是机械冲击,它起源于迅速蒸发与膨胀的高温蒸气对样品表面所施加的压力。

Investigation on physical mechanism of shock waves in materials generated by Q-switched laser beam

Using a Q-switched ruby laser pulse to cause a transient heating of silver film on the surface of a piezoelectric ceramic sheet, the investigation on the physical mechanism of laser generated shock wave in absorbing materials has been performed. It is shown from the analysis of the obtained electrical signals that there are two types of physical mechanisms for laser generated shock waves: one is the thermal shock, which is due to the thermal expansion and the giant stress gradient following the rapid absorption of laser pulse energy at the surface layer of an elastic specimen; the other is the mechanical shock, which is due to the rapidly vaporizing and expanding of the high temperature vapor which exerts a pressure on the target surface.