Fir josephson photoresponse of tilted c-axis epitaxial YBa2Cu3O7-δ

Far infrared video detection and difference frequency mixing with tilted c-axis epitaxial YBa2Cu3O7−δ thin films

“…In contrast, the 4.2 K signal remained nearly constant over the frequency range studied ͑5 Hz-3 kHz͒. The low temperature photosignal was found to be proportional to incident power, i.e., square law: a previous pulsed laser study 11 has established a sub-linear dependence on power at higher incident powers and a ns response speed. The nonbolometric signal origin is also confirmed by comparison with the purely bolometric response to chopped 685 nm radiation from a semiconductor diode laser.…”