30 December 2008 Optimization of laser-damage resistance of evaporated hafnia films at 351nm
Author Affiliations +
A systematic study was undertaken to improve the laser-damage resistance of multilayer high-reflector coatings for use at 351 nm on the OMEGA EP Laser System. A series of hafnium dioxide monolayer films deposited by electron-beam evaporation with varying deposition rates and oxygen backfill pressures were studied using transmission electron microscopy (TEM), x-ray diffraction (XRD), and refractive index modeling. These exhibit microstructural changes for sufficiently slow deposition rates and high oxygen backfill pressures, resulting in an absence of crystalline inclusions and a lower refractive index. Hafnia monolayers exhibited laser-damage resistance as high as 12 J/cm2 at 351 nm with a 0.5-ns pulse. This process was utilized in the fabrication of reduced electric-field-type multilayer high-reflector coatings. Measured laser-damage thresholds as high as 16.63 J/cm2 were achieved under identical test conditions, an exceptional improvement relative to historical damage thresholds of the order of 3 to 5 J/cm2.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. B. Oliver, J. B. Oliver, S. Papernov, S. Papernov, A. W. Schmid, A. W. Schmid, J. C. Lambropoulos, J. C. Lambropoulos, } "Optimization of laser-damage resistance of evaporated hafnia films at 351nm", Proc. SPIE 7132, Laser-Induced Damage in Optical Materials: 2008, 71320J (30 December 2008); doi: 10.1117/12.805383; https://doi.org/10.1117/12.805383

Back to Top