Provided is an infrared radiation detector comprising an active layer having a front side and a back side. An anti-reflective coating is disposed on the front side and is configured to minimize reflection of incident light within a wavelength band of interest upon the front side. A highly-reflective coating is disposed on the backside and is configured to increase reflection within the wavelength band of interest upon the back side. Each one of the anti-reflective coating and highly-reflective coatings are comprised of a quarterwave stack of a plurality of layers each having an optical thickness equal to one-fourth of the wavelength band of interest. The wavelength band of interest is preferably in the range of from about 3.0 to about 5.0 microns.