Abstract

Thin film optical coatings made by ion beam sputter deposition (IBSD) have excellent optical properties, such as high refractive index, low absorption and low scatter. In addition, IBSD films can be produced without applying external heat to the substrates. These properties make IBSD coatings suitable for low-loss applications, such as ring laser gyroscope mirrors and resonator mirrors in high-energy lasers.¹ One limitation of these coatings is that the materials have a high compressive stress which can significantly distort an optic coated with a thick multilayer IBSD coating.² Several techniques have been demonstrated for modifiying the intrinsic stress in thin films, including ion bombardment of the growing film, altering deposition parameters and combining two materials by coevaporation or cosputtering.³

© 1988 Optical Society of America