SENSITIVE PICOSECOND NBN DETECTOR FOR RADIATION FROM MILLIMETER WAVELENGTHS TO VISIBLE-LIGHT

We report on the application of a broad-band NbN film detector which has high sensitivity and picosecond response time for detection of radiation from millimetre wavelengths to visible light. From a study of amplitude modulated radiation of backward-wave tubes and picosecond pulses from gas and solid state lasers at wavelengths between 2 mm and 0.53-mu-m, we found a detectivity of 10(10) W-1 cm Hz-1/2 and a response time of less than 50 ps at T = 10 K. The characteristics were provided by using a 150 angstrom thick NbN film patterned into a structure of micron strips. According to the proposed detection mechanism, namely electron heating, we expect an intrinsic response time of approximately 20 ps at the same temperature.