Picosecond photoresponse of epitaxial YBa2Cu3O7−δ thin films

Photoresponse signals as fast as 16 ps (full width at half-maximum) have been observed from current-biased bridge structures of epitaxial YBa2Cu3O7−δ thin films on LaAlO3 using 5 ps, 820 nm laser pulses. Operating at liquid-nitrogen temperature (77.4 K), the amplitude of the fast response was found to be linear with current at low bias currents. At higher bias currents, a slow component appeared in the signal with a decay over several …