OPTICAL COATINGS DEPOSITED BY REACTIVE ION PLATING

The effect of different reactive ion-plating process parameters on the transmittance and the reflectance of single layers of HfO2, Ta2O5, and SiO2 are investigated. The optical constants obtained for these three as-deposited materials are presented. Laser-damage threshold trends are examined on single- and double-layer coatings at 1064 nm and on high-reflectance coatings for 248 nm. Single- and double-cavity filters are constructed for the UV (< 1-nm bandwidth) and near-infrared (50-nm bandwidth) regions, respectively. After the filters are postannealed in air at 375-degrees-C for several hours, a shift in the peak wavelengths is observed along with a substantial increase in the peak transmittance. As expected, no significant wavelength shifts result from changes in the humidity of the ambient atmosphere.