The present invention comprises a system and method for detecting multiple wavelength bands of infrared radiation. The present invention incorporates an optical concentrator or "optical funnel" to increase the energy density on the detection elements and discrete filters mounted in the funnels and a mounting structure for individual detector elements. An apparatus in accordance with the present invention is an advance over conventional infrared detector assemblies in several areas. The apparatus in accordance with the present invention provides a unified means for mounting detectors, optical concentrators and infrared filters. It also provides an efficient means for electrical connection to the detector elements. The present invention provides a mounting structure for the detectors bonding them directly to the body of the optical funnel and passing light into them from the "backside" of the detector elements. The present invention prevents cross talk by mounting the detector elements at the focused end of individual optical concentrators.