STRUCTURAL-CHANGES IN GAAS INDUCED BY ULTRAFAST (FS) LASER-PULSES

Ultrafast changes in the crystal structure of GaAs induced by intense femtosecond laser pulses are detected and investigated. Atomic force m icroscopy and Raman microprobe analysis of the laser-treated area show centrosymmetric (disordered) features which are different from the or iginal zinc-blend structure of the GaAs lattice. The frozen-in structu re shows evidence for a special heat transfer from the laser-induced c rater to the boundary, namely the heat has been transferred ballistica lly by a high-density electron-hole plasma.