CVD-diamond optical lenses

Diamond lenses are highly desirable for a variety of optical applications including the operation under high-power, high thermal load and under harsh environmental conditions. We report on the realization of CVD-diamond lenses by deposition on structured substrates. Lenses with diameters between 2 and 5 mm and focal lengths between 3.2 and 5.2 mm were prepared. Substrates with a spherical surface or with an array of spherical impressions have been used. CVD-diamond of high phase purity was deposited on these structured substrates using microwave plasma CVD. The growth side of the diamond layer was polished and the substrate removed. Laser cutting separated the lenses. The plano-convex CVD-diamond lenses prepared with this "molding" technique were characterized regarding flatness and spherical aberration of the individual surfaces as well as optical and thermal properties.