Development of wide-band, time and energy resolving, optical photon detectors with application to imaging astronomy

Superconducting transition edge sensors (TESs) are showing promise for the wide-band spectroscopy of individual photons from the mid-infrared (IR), th rough the optical, and into the near ultraviolet (UV). Our TES sensors are similar to 20 mu m square, 40 nm thick tungsten (W) films with a transition temperature of about 80 mK. We typically attain an energy resolution of 0. 15 eV FWHM over the optical range with relative timing resolution of 100 ns . Single photon events with sub-microsecond risetimes and few microsecond f alltimes have been achieved allowing count rates in excess of 30 kHz per pi xel. Additionally, tungsten is approximately 50% absorptive in the optical (dropping to 10% in the IR) giving these devices an intrinsically high quan tum efficiency. These combined traits make our detectors attractive for fas t spectrophotometers and photon-starved applications such as wide-band, tim e and energy resolved astronomical observations. We present recent results from our work toward the fabrication and testing of the first TES optical p hoton imaging arrays. (C) 2000 Published by Elsevier Science B.V. All right s reserved.