Correlations between the oxygen deficiency and the laser damage resistance of different oxide films

Abstract Ta 2 O 5 , ZrO 2 and HfO 2 films are deposited on BK7 substrates by electron beam evaporation method. The effects of oxygen deficiency on the optical properties and laser-induced damage threshold (LIDT) are investigated by the combination of experimental methods and first principles calculations. The results show that the oxygen deficiency weakens the transmittance, whereas it enhances the absorption of all the films. Once the oxide vacancy appears, the band gaps decrease greatly, which seriously decrease the LIDT. The calculated negative vacancy energies indicate that, when the oxygen vacancy exists, Ta 2 O 5 is most easily to be damaged, next is ZrO 2 and the last is HfO 2 . It is consistent with the LIDT results that Ta 2 O 5 increases 64.8%, ZrO 2 increases 19.4% and HfO 2 increases 12.9% when the oxygen vacancy is eliminated.