Optimization of laser-damage resistance of evaporated hafnia films at 351nm

J. B. Oliver, S. Papernov, A. W. Schmid, J. C. Lambropoulos, Gregory J. Exarhos, Detlev Ristau, M. J. Soileau, Christopher J. Stolz
2008 Laser-Induced Damage in Optical Materials: 2008  
Crystallites are present in typical evaporated hafnia films, negatively impacting laser-damage threshold (LDT). • Deposition rate and O 2 backfill pressure influence the refractive index of hafnia deposited by reactive e-beam evaporation. • Low deposition rate and high O 2 backfill pressure yields a porous, mechanically fragile film sensitive to changes in relative humidity. -sensitivity is apparent in LDT, with changes of the order of 20% for observed fluctuations in ambient relative humidity.
more » ... -LDT is significantly improved (3#) for sufficiently low deposition rates and high O 2 backfill pressure; mirrors have been deposited with LDT as high as 16.63 J/cm 2 (0.5 ns, 1:1 testing protocol).
doi:10.1117/12.805383 fatcat:lxe4pjdwevdxrj6llepyu4tgyy