SiO2 antireflection layers for single-crystal diamond

Single crystalline diamond is of interest for high power optical applications for a variety of reasons including transparency, high thermal conductivity and very low birefringence values. Potential applications include intracavity diamond components for thermal management in high power lasers in which case optical antireflection coatings are of interest. This paper addresses the use of PECVD SiO 2 as an antireflection coating on diamond for near-infrared applications. Modeling shows that with appropriate selection of film thickness, absorption free SiO 2 layers on the front and back of a diamond plate can theoretically result in 99.1% transmission at the center wavelength for the antireflection coatings. This paper reports an experimentally achieved maximum transmission of 98.7%, with a standard deviation of 0.4%, centered on an optical wavelength of 1.62 m. Initial tests of film adhesion and robustness were performed.