Influence of Post-Deposition Treatment by UV Light and Oxygen (Ozone) on 350 NM Damage Thresholds of SiO sub 2 Films Deposited from Sols

摘要

Certain multilayer porous silica AR (antireflection) coatings on fused silica substrates prepared by the sol-gel process have been found to have a much lower laser damage threshold than single layer coatings prepared by the same method. Treatment with uv light in the presence of oxygen (which gives ozone) at low temperatures was found to restore damage thresholds to the levels found in single layers. Damage thresholds were measured at 350 nm with a 25 ns pulse for 1000 shots at 25 Hz. The effect of exposure time and other factors such as replacement of oxygen with nitrogen and vacuum are described. 1 ref., 2 figs., 1 tab. (ERA citation 13:006082)