Wide-angle infrared absorber based on a negative-index plasmonic metamaterial

A metamaterial-based approach in making a wide-angle absorber of infrared radiation is described. The technique is based on an anisotropic perfectly impedance-matched negative-index material (PIMNIM). It is shown analytically that a PIMNIM that is subwavelength in all three dimensions enables absorption close to 100% for incidence angles up to 45 degrees to the normal. A specific implementation of such frequency-tunable PIMNIM based on plasmonic metamaterials is presented. Applications to infrared imaging and coherent thermal sources are described.