Far-Infrared Trapping Detector with Nearly Ideal Response

We have developed a cryogenic infrared detector with nearly unity quantum efficiency over the spectral range from 4 $\mu $m to 24 $\mu $m. This light-trapping device is composed of two Si:As blocked-impurity-band (BIB) detectors in a wedge geometry behind a 1 mm entrance aperture. Operated at a temperature of 10 K, the device exhibits significant responsivity from 2~$\mu $m to 30~$\mu $m and dark current less than 30 nA. Compared to HgCdTe detectors, these silicon-based trapping devices exhibit higher sensitivity, more uniform spatial response, and a spectral range which extends further into the far-infrared. This trap detector could be particularly useful as a mid-infrared and far-infrared transfer standard, with nearly ideal photodetector response at the 10.6 $\mu $m line of CO$_{2}$ lasers.