REACTIVELY SPUTTERED OXIDE OPTICAL COATINGS FOR INERTIAL CONFINEMENT FUSION LASER COMPONENTS

Results to date are presented for a study of reactively sputtered oxide optical coatings which are candidate materials for use in the NOVA Terawatt neodymium glass laser under development at Lawrence Livermore Laboratory, Livermore, California. Experimental details are described for the deposition of TiO2 on fused silica substrates by r.f. diode sputtering of titanium in a reactive Ar-O2 atmosphere. Specific deposition procedures are presented for variation of the phase composition and grain size of the coatings over wide ranges. High laser damage thresholds are reported for TiO2, and glassy coatings appear to be more damage resistant than polycrystalline coatings. Phase composition appears to be less important to damage resistance than grain size. Application of the reactive sputtering process to preparation of damage-resistant oxides of In-Sn and tantalum is also described and damage thresholds obtained to date are reported. © 1979.