PICOSECOND PHOTOEMISSION STUDIES OF THE LASER-INDUCED PHASE TRANSITION IN SILICON.

Abstract

Four different regimes of photoelectric emission are observed over a wide fluence range of UV-laser pulses irradiating single crystal silicon samples. The role of the electron-hole plasma in the nonlinear photoemission is demonstrated by temporal correlation measurements. A regime where ion thermal evaporation processes take place is observed above the critical fluence for melting. At higher laser fluences, nonlinear ion acceleration is demonstrated by direct time-of-flight measurements.