Enhanced Emissivity in High-Speed Window Materials

Protective windows for infrared sensors in high aerothermal load conditions are subject to high mechanical force, self-emission, environmental effects, and to failure due to thermal shock.  This program will demonstrate new ceramic compositions expressly engineered for high temperature infrared transparent windows having high transmissivity, increased thermal shock resistance, high strength at high temperature, and reduced self-emission at wavelengths critical to infrared sensors.  The ceramic windows will be based on an oxide with carefully selected additives that will tune the absorption spectrum for enhanced cooling and controlled emissivity.  The method for controlling absorption and emissivity in these new composite materials will lead to increased thermal shock resistant windows without affecting optical performance.  Advanced manufacturing methods will be employed to produce material microstructures that will provide high mechanical strength.  Sub-scale apertures will be fabricated to demonstrate a robust material capable of providing infrared sensor protection in extreme environments while maintaining the optical performance required for high precision infrared sensor operation.  The new material compositions and manufacturing methods demonstrated and matured in this program will also be applicable to other transparent ceramic oxide systems.  The output of this program’s work to additional materials will lead to a broad range of new material compositions having enhanced cooling and controlled transmissivity.  This in turn will expand the application space and use environments for many UV-Visible, SWIR and extended MWIR seeker systems.