Role of degeneration processes in picosecond nonlinear spectroscopy of HTSCs

It is shown that both spectral-temporal and temperature anomalies of the reflectance and transmittance kinetics of high-temperature superconducting films at high 'impact' excitation levels have a direct analogue in the case when much longer and coincident in time picosecond pulses are used to excite and probe the film state. In this case, due to degeneration, the nontrivial (with a sharp jump in the vicinity of the phase transition point) dependence of the nonlinear response amplitude of a sample on its initial temperature should be observed.