Superconducting granular NbN bolometer for ultrafast spectroscopy

A superconducting ultra thin granular NbN bolometer has been developed for the ultrafast detection of phonons and photons over a wide spectral range. This bolometer consists of an rf reactively sputtered film of NbN anodized to a final thickness of 30A. It operated over a wide temperature range (<1.4 to 14 K) has ultrafast response (<0.1 nanoseconds) and has demonstrated sensitivity to phonons in insulators, glasses and semiconductors, to microwaves and to infrared and optical photons. The response is nearly uniform over its temperature range and is linear with absorbed power.