RESONANT MULTIPHOTON PROCESSES IN LASER-SURFACE INTERACTION

When the surface of a transparent divalent ionic crystal is irradiated by intense pulses from a visible dye laser, resonant multiphoton processes are observed, such as optical second harmonic generation or multiphoton photoemission and laser-induced desorption of surface constituents. The resonant behaviour may be explained on the basis of calculations on an embedded cluster as a theoretical model for the surface