An infrared sensor element having an antenna coupled directly into a rectifier. Infrared radiation impinging the antenna induces an alternating current. The rectifier converts the alternating current into a rectified signal. The rectified signal corresponds to a magnitude of the incident infrared radiation impinging the antenna, and can be used for detection and imaging operations. Coupling the antenna directly into the rectifier eliminates the need for a photodetector. The wavelength of sensor elements can be separately tuned. A sensor made up of a plurality of such sensor elements can operate in a time-division multiplexed mode sensing different infrared bandwidths in separate time segments. Two or more sensors each made up of a plurality of sensor elements can be co-located in a single focal plane and operated separately to detect infrared radiation in different bandwidths. A sensor element can also operate in bandwidths other than infrared.