Electrical picosecond measurements of the photoresponse in YBa2Cu3O7−x

Abstract
Ultrafast transient voltage pulses (rise time 12 ps, width 29 ps) have been observed at 50 K across a current‐biased very thin YBa2Cu3O7−x epitaxial film (thickness 30 nm) when illuminated by short laser pulses. The accuracy of the present measures shows the system reaction during the first tens of picoseconds. Such very narrow photosignals can be described as related to nonequilibrium phenomena. The measured decay times corroborate the biexponential escape of the deposited energy described by other authors.