OPTICAL CONTRAST BY LASER-INDUCED PHASE-CHANGES - REAL-TIME OPTICAL MEASUREMENT OF FAST TRANSFORMATION TIMES

Real time optical measurements are used to analyse two different kinds of phase changes which generate optical contrast in (In43Sb57)87Ge13 thin films. Amorphous to crystalline and amorphous to amorphous struct ural transformations are induced by pulsed laser irradiation in micron -sized regions. A two beam configuration is used to follow the evoluti on of the optical properties of the films in real time. It is shown th at real time optical measurements provide a unique tool to analyse las er-induced fast structural transformations leading to optical contrast . Processes occurring via relaxation, solid state crystallization or m elting-solidification are clearly distinguished. From the analysis of the optical transients the minimum transformation times are directly d etermined.