NONEQUILIBRIUM KINETIC INDUCTIVE RESPONSE OF YBACUO THIN-FILMS TO LOW-POWER LASER-PULSES

Transient non-equilibrium kinetic inductive voltage response of YBaCuO thin films to 20 ps pulses of YAG:Nd laser radiation with 0.63 mu m a nd 1.5 mu m wavelength has been revealed. By increasing the sensitivit y of 100 ps resolution time registration system and diminishing light intensity (fluence 0.1-1 mu J(2)/cm(2)) and transport current (density j less than or equal to 10(5) A/cm(2)) we observed a perculiar bipola r signal form with nearly equal amplitudes of each sign. The integrati on of the kinetic inductive response over time gives the result which is qualitatively of the same form as the response in the resistive and normal states: nonequilibrium picosecond scale component followed by bolometric nanosecond. Nonequilibrium response is interpreted as suppr ession of order parameter by excess of quasiparticles followed by a ch ange in resistance in the resistive state and kinetic inductance in su perconductive state.