熔石英光学材料紫外皮秒激光损伤的瞬态特性研究

光学元件激光损伤是限制高功率激光装置输出能力的关键因素,为了理解光学元件激光损伤过程,提高光学元件抗激光损伤性能,利用偏振阴影显微镜成像技术和光电探测技术研究了紫外皮秒激光诱使熔石英光学元件损伤的时间分辨动力学过程。结果显示了紫外皮秒激光作用过程中冲击应力波的传输特性、瞬态吸收的演变过程以及裂缝的发展过程。结果表明,冲击应力波的传输速度约为6.9μm/ns;532nm波长的激光瞬态吸收在激光作用之后2.5μs时激光吸收达到最大值,之后缓慢下降,整个持续时间可达50μs以上;损伤裂纹在7.5ns时刻就基本停止增长。研究结果对理解皮秒激光的损伤机制有重要意义。

Time Resolved Studies of Material Response During Ultraviolet Picosecond Laser-Induced Damage in Fused Silica

To understand laser induced damage mechanism of optics, the damage dynamics of fused silica induced by ultravio- let picosecond laser is investigated using shadow graphic and laser-deflection imaging technique and photoelectric detection technique. The results show that shock/pressure wave propagation, transient absorption and crack propagation evolve dur- ing ultraviolet picosecond laser irradiation. The speed of propagation of shock/pressure wave is about 6.9 μm/ns. The tran- sient absorption of damage region remains absorbing until 50μs. The maximum absorption is reached 2. 5 μs delay. The cracks stop growing at the 7. 5 ns delay.