Infrared Metamaterials for Emission Phase Control

ABSTRACT: Electromagnetically-resonating infrared metamaterial elements may be used to control the phase of emitted radiation across a planar surface. Such a coated surface can be designed to produce a highly directional emitted wavefront from a large aperture high-angular-resolution array. Active angular control may be achieved using electronically-tunable metamaterial elements. Like all phased-array devices, the spectral response of the metamaterial array is inherently narrow band, but electronic tuning can allow the device to operate at wavelengths across the long-wave or mid-wave infrared. A metamaterial-populated surface is a patterned thin-film coating that adds almost no mass to the application. Such a surface may also be made to be environmentally ruggadized. Furthermore, thermally sensitive materials may be incorporated to direct heat away from hot-spots. BENEFIT: Directional control of thermal emission is of interest to the Air Force for space platforms. Further commercial applications include infrared-energy harvesting and related infrared active optical systems. Infrared energy harvesting has many potential applications, and is especially attractive for applications where low power is required and collection of solar energy is not feasible. Due to their light-weight, electronically-controlled active infrared optical systems have a variety of aerospace applications.