  A metamaterials-based approach to 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 sub-wavelength in all three dimensions PIMNIM enables absorption of
close to 100% for incidence angles up to $45\deg$ 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.
