Influence of outgassing organic contamination on the transmittance and laser‐induced damage of SiO2 sol‐gel antireflection film

The influence of organic contamination (rubber outgassing) on the transmittance of the SiO 2 sol‐gel antireflection (AR) film and laser‐induced damage threshold (LIDT) at 355 nm for 3 ω AR film and at 1064 nm for 1 ω AR film is studied. The correlation between the contamination time and the transmittance loss/LIDT of 1 ω /3 ω AR film is also investigated both in atmospheric and vacuum environments. The results show that the transmittance loss increases with increasing contamination time, and the LIDT decreases with increasing contamination time for both in atmospheric and vacuum environments. In addition, the resistance against contamination of the 1 ω film is stronger than 3 ω film, and the contamination is more serious in vacuum than in an atmosphere environment for the same contamination time. Meanwhile, the damage mechanism is also discussed. It indicated that both the porous structure and photo‐thermal absorption contribute to the decreasing LIDT of the sol‐gel AR film.