PHYSICAL SCIENCES INC. — Department of Defense SBIR Phase I: N231-065

Description

The Navy requires fast, frequency-agile, stimuli-responsive and tunable micromirror surfaces to keep focal plane array (FPA) MWIR irradiance levels below the damage threshold without losing track of the MWIR target. PSI proposes a Cooperative Optically Responsive MWIR Filter (CORE-MF) that simultaneously achieves requirements for fast autonomous actuation, rapid recovery time, and long-term endurance. CORE-MF consists of a COTS DMD where the window has been replaced by a custom MWIR-transmissive Intensity Dependent Infrared Attenuator (IDIRA) consisting of a vanadium oxide (VO2) coating on a MWIR-transmissive substrate. The CORE-MF acts as an in-line reflective filter in a larger imaging sensor. Targets with MWIR radiation below acceptable damage thresholds pass through the CORE-MF unchanged. As target radiance increases energy is absorbed locally, causing local heating of VO2, and reducing MWIR transmission only where heating occurs. A second-level of spatially-selective attenuation is provided by the DMD via fast binary half-toning for the brightest objects. The net result is a dual-stage cooperative optically-responsive MWIR filter capable of delivering >10,000x attenuation only where needed. During the Phase I program, IDIRA substrate and coating fabrication will be advanced, a concept for custom compact DMD controllers will be developed and a functional alpha CORE-MF prototype will be demonstrated.