激光辐照TiO_2/SiO_2薄膜损伤时间简捷测量

Simple time measurement of TiO_2/SiO_2 film damaged by laser

为了测量激光辐照薄膜的起始时间,采用了一种简洁易行的测量方法,利用波长1.06μm和1.315μm连续激光以及1.06μm单脉冲激光辐照典型薄膜光学元件,通过探测器接收激光脉冲信号和薄膜表面的激光反射信号,薄膜表面反射信号在激光辐照过程中的某个时刻发生突变,发生突变的时间对应着薄膜发生损伤的时间。得到1.06μm连续激光强度为7133W/cm2时,反射信号在0.8 s发生突变,强度为11776W/cm2时,反射信号在0.4 s发生变化;1.06μm单脉冲激光能量为48.725m J,97.45m J,194.9m J时,薄膜损伤时间为3.63ns,2.727ns和1.09ns;1.315μm连续激光强度为2743W/cm2时,反射光信号在辐照时间t=3.44 s发生突变;强度为4128W/cm2时,薄膜表面反射光信号在辐照时间t=1.44 s发生突变。结果表明,通过测量薄膜表面反射信号的突变来确定薄膜损伤的起始时间,对于薄膜抗激光加固,以及提高光电系统的抗激光能力有着重要的意义。

A simple method was used to study the initiative time of the thin film irradiated by laser, in which adopting 1.06μm, 1.315 μm CW laser and 1.06 μm single pulse to irradiate typical optical film elements, laser reflex from the surfaces of film elements was measured reflected signal happened to change in a certain time, which is in accordance with time of film damaged by laser. The damaged time was 0.8s and 0.4s when 1.06μm CW laser density was 7133W/cm^2 and l1776W/cm^2 respectively. The damage time was 3.63ns, 2. 727ns and 1.09ns when 1.06μm single pulse laser energy was 48. 725mJ, 97.45m J, 194.9mJ respectively. The damaged time was 3.44s and 1.44s when 1.315 μm CW laser density was 2743W/cm^2 and 4128W/cm^2 respectively. Result shows the method of measuring reflected signal of damaged thin films can obtain damaged time of film and it is hepful for improving the laser-resistance of film.