Nanostructured Optical materials to enhance lethality of IR countermeasures

This proposal aims to establish a domestic manufacturing facility for the production of nano-structured optical (NSO) surface infrared (IR) anti-reflection (AR) treatments applied to IR crystals to enhance the lethality of infrared countermeasure (IRCM) and directed energy weapons (DEW) systems. Nanohmics Inc. (Austin, TX), working in support with AFRL Materials and Manufacturing (AFRL/RXE), AFRL Air Mobility Command (AFRL/AMC), BAE Systems (see letter of support), and The University of North Carolina, Charlotte (UNCC, see letter of support) will fabricate and characterize AR NSO treatments on Zinc Germanium Phosphide and Cadmium Silicon Phosphide ľ two state-of-the-art nonlinear crystals that can generate high-power mid-infrared (MWIR, wavelength = 3ľ5 micrometers) lasing. High-power, high-efficiency, broadly-tunable coherent sources in the MWIRáspectral band are coveted for infrared (IR) countermeasures, remote chemical sensing, and free-space optical communication. Sources based on optical nonlinear frequency conversion can generate broadly-tunable kilowatt-level coherent radiation over the entire MWIR spectrum. One factor that limits the source performance is the low optical damage threshold of anti-reflection thin-film coatings applied to the surfaces of the nonlinear crystal. Thin films absorption loss becomes prohibitively large at high optical intensities, and films subsequently are damaged due to thermal effects. Replacing thin film treatments anti-reflective nano-structured optical treatments have the potential to significantly increase the optical damage threshold given that that the structures are monolithically etched in the surface of the nonlinear crystal. Nanohmics Inc. proposed to develop a lithography-free method of applying random anti-reflective surface structure (rARSS) treatments to Zinc Germanium Phosphide and Cadmium Silicon Phosphide nonlinear crystals. The team will demonstrate that its Ĺthermodotĺ-based rARSS technology is a simple and cost-effective method to manufacture broadband (1.5 ľ 6 micron) AR treatments with superior damage thresholds compared to typical AR thin films. áááá