Simple time measurement of TiO2/SiO2 film damaged by laser

A simple method was used to study the initiative time of the thin film irradiated by laser,in which adopting 1.06μm,1.315μm CW laser and 1.06μm 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/cm2 and 11776W/cm2 respectively.The damage time was 3.63ns,2.727ns and 1.09ns when 1.06μm single pulse laser energy was 48.725mJ,97.45mJ,194.9mJ respectively.The damaged time was 3.44s and 1.44s when 1.315μm CW laser density was 2743W/cm2and 4128W/cm2 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.