【摘要】 本文研究了在自由振荡钕玻璃激光照射下LY12铝靶产生喷溅的物理机制及特性。这种幅度与时间无规律变化的激光序列尖峰脉冲的单个脉冲宽度约2μs,脉冲间隔约5μs。在这些脉冲作用下产生的喷溅过程也呈现相应的序列特性。在10~7W/cm~2的激光平均功率密度下,个别的尖峰脉冲功率密度可大于10~8W/cm~2。用分幅和扫描高速相机分别测量速度较低的喷溅物汽化运动图象,观察到了以7.7mm/μs的速度逆着入射激光方向传播的靶蒸汽和等离子体的喷溅过程,这相应于激光吸收波现象,并发现有屏蔽效应。更多还原

【Abstract】 The physical mechnism and characteristics of the blow off from a LY-12 aluminum target irradiated by a pulsed Nd: glass laser beam are investigated in this paper. The laser beam consists of a series of pulses with a duration of about 2μs for each and a time interval of about 5 - 10 μs between two adjacent ones. The blow off process shows a time-dependent behavior similar to that of the laser beam irradiating the target. For the beam of mean power-density of 107W/cm2, some spikes are higher than 108W/cm2. The blow off is measured by framing and streak photography. Besides the vaporization and slower blow off, it is found that there exists a vapor and plasma blow off process directed upstream to the laser beam with a speed of 7.7mm/μs, which should be the laser absorption wave phenomenon. In addition plasma shielding effects seem to be observed.更多还原