Anomalous photoresponse of metal films

Abstract
Current biased samples are illuminated by short pulses of laser light and voltages are measured for a range of temperature 7 K<T<350 K. Classically, no response is expected for times greater than 10 ps after the pulse arrival. However, transient signals with temperature-independent decay times are observed in Ni and Nb samples, and a similar signal with diminished amplitude is observed in a Au sample.