Femtosecond laser damage resistance of oxide and mixture oxide optical coatings

Abstract

We report on the laser damage resistance of ion beam—sputtered oxide materials (${\mathrm{Al}}_2{\mathrm{O}}_3$, ${\mathrm{Nb}}_2{\mathrm{O}}_5$, ${\mathrm{HfO}}_2$, ${\mathrm{SiO}}_2$, ${\mathrm{Ta}}_2{\mathrm{O}}_5$, ${\mathrm{ZrO}}_2$) and mixtures of ${\mathrm{Al}}_2{\mathrm{O}}_3\text{-}{\mathrm{SiO}}_2$, ${\mathrm{Nb}}_2{\mathrm{O}}_5\text{-}{\mathrm{SiO}}_2$, ${\mathrm{HfO}}_2\text{-}{\mathrm{SiO}}_2$, ${\mathrm{Ta}}_2{\mathrm{O}}_5\text{-}{\mathrm{SiO}}_2$, and ${\mathrm{ZrO}}_2\text{-}{\mathrm{SiO}}_2$, irradiated by single 500 fs pulses at 1030 nm. Laser-induced damage threshold (LIDT), refractive index, and bandgaps of the single-layer coatings are measured. For pure oxide materials a linear evolution of the LIDT with bandgap is observed. The results are in accordance with our simulations based on photo-ionization and avalanche-ionization. In the case of mixtures, however, deviations from the previous behaviors are evidenced. The evolution of the LIDT as a function of the refractive index is analyzed, and an empirical description of the relation between refractive index and LIDT is proposed.

© 2012 Optical Society of America