Aerospace applications of resonant optical lattices in the IR spectral domain

The long-wave infrared (LWIR) electromagnetic band covers a region of atmospheric transparency essential for terrestrial imaging, spectroscopic applications, night-vision systems, and medical and industrial laser technologies. To utilize this band for such applications, efficient, low-loss components including reflectors, filters, and polarizers must be available. Components made of dielectric media are lightweight and have a low radar cross section in contrast to metals. For the LWIR band, traditional thin-film technology is generally not applicable on account to the extreme film thicknesses required and associated long film deposition time. New solutions that are neither based on metals nor thin-film stacks are needed. Accordingly, here we review developments in alternate technology based on single-layer resonant gratings. Following explanations of the basic physical principles at work, we present examples of optical components that are realizable with this methodology. Design of a robust LWIR wideband reflector and tunable notch filter is presented. Experimental results showing performance of a wideband reflector, dually polarized notch filter, and angularly tunable filters are shown along with SEM/AFM device characterizations. These compact, lightweight, low-loss, and robust devices are highly suitable in various aerospace applications including imaging and sensing.