LASER-INDUCED GRATING SPECTROSCOPY OF HIGH-T(C) SUPERCONDUCTORS

We propose a new spectroscopical method for the investigation of ultra fast phenomena in metallic and high-Tc superconductors by using tunabl e laser beams, without requiring femtosecond laser pulses. The method is based on the self-diffraction of a laser beam from a laser-induced moving grating. The theory of the method has been developed in detail for the case of electron-phonon (EP) interaction. Our theoretical pred ictions are in good agreement with a recent experiment. Using experime ntal data we estimated the value of the EP coupling constant for the Y Ba2Cu3O7 film.