The hot-electron microbolometer as an ultrasensitive detector for millimeter wavelengths

The hot-electron microbolometer is a novel low-temperature thermal detector which has potential for very low-noise power measurements at millimeter wavelengths. We are investigating issues in the practical implementation of this detector for low-background applications. We present results from tests of an efficient scheme to couple the detector to waveguide, as well as the expected noise performance of a microbolometer optimized for balloon-borne measurements. The expected NEP of microbolometer in such a measurement is 7/spl times/10/sup 18/ W//spl radic/(Hz) which is nearly a factor of two better than bolometers currently in use.<>