强飞秒激光烧蚀石英玻璃的超快时间分辨光学诊断

采用超快时间分辨的光学诊断技术对飞秒激光脉冲烧蚀石英玻璃的动态过程进行了实验研究.首先,对烧蚀过程中石英玻璃外部的物质喷射进行了数字全息记录,获得了不同延迟时间下探测光的二维相位差分布图,并由此推断出了喷射物的成分和结构.此外,对石英玻璃内部的现象进行了时间分辨阴影图记录,从阴影图中观察到了石英玻璃内部的两个应力波的演化过程.这两个应力波与目标靶外部的两次物质喷射相关.关键词：脉冲数字全息飞秒激光烧蚀超快时间分辨应力波

Time-resolved optical diagnosis of intense femtosecond laser ablation of silica glass

The dynamic process of femtosecond laser pulse ablation of silica glass has been experimentally investigated by ultrafast time-resolved optical diagnosis. The digital holograms of material ejections outside the silica glass are recorded, and two-dimensional phase difference maps at different delay times are obtained, from which the composition and the structure of the ejected materials are deduced. Besides, the time-resolved shadowgraphs of the phenomena inside the silica glass are also recorded, and the evolution process of two stress waves inside the silica glass is observed in the shadowgraphs, which are believed to be related to two material ejections outside the target.