Hyperspectral Infrared (IR) Windows

Multispectral zinc sulfide, because of its good optical transmittance in the visible, near infrared, MWIR, and LWIR spectral bands, is one of a number of materials used extensively as a “hyperspectral” window. Such windows serve as primary protection for sensitive multi-band electro-optic instrumentation or sensors in aerospace platforms (missile, aircraft, UAV, rotorcraft, etc.). It is critical in most of these applications that the hyperspectral window resist erosion from raindrops and dust encountered during flight, and that spectral transmittance is not degraded as a result. Multispectral Cleartran windows have poor erosion resistance and so a protective coating is required for applications where impact with sand, dust, or raindrops is anticipated. Furthermore, the relatively high refractive index of Cleartran windows causes significant reflection losses at each material interface, unless special anti-reflective coatings are applied. Nanohmics proposes an applied research program with the aim of creating and characterizing a patterned surface for Cleartran windows that reduces optical reflections over a broad spectral range, in addition to providing enhanced protection from rain and sand erosion. BENEFIT: The continued design and development of coating and patterning technology and the successful construction and demonstration of initial prototype hyperspectral windows to provide to development/manufacturing partners for airborne testing are the overall goals of the program. Technical success will lead to sales of window components to defense system contractors for advanced sensors, seekers, and airborne surveillance platforms.