Corrosion-Resistant Anti-reflection (AR) Coating of High Energy Alkali Laser Components Using Refractory Materials

Realization of high-performance compact lasers will require the development of substrates and advancements in optical coatings that can withstand the harsh environments of corrosive gases, high temperatures, and high energy densities. Toward this end we intend to undertake the development of novel optical coatings that will simultaneously provide the necessary protection and maintain the optical performance of coated components to the desired levels. Specifically, the proposed multi-layer index-matching coating(s) will be designed to ensure maximum transmission and minimum reflectance at the D1 and D2 wavelengths of rubidium. Furthermore, its chemical structure will be resistant not only to rubidium vapor, but also to its oxides and hydroxides. Computer modeling of the layered structure will be performed to study its light transmission properties. During Phase I, the efficacy of our approach was demonstrated by coating sapphire substrates used in Diode Pumped Alkali Laser Systems (DPALS). The Phase II program will logically extend the Phase I research to complete the development of coatings and their testing in a realistic environment. To ensure successful development, and to facilitate technology transition to commercialization, we have teamed with a well-known company currently developing DPALS for commercial use. Approved for Public Release 14-MDA-7739 (18 March 14).