Optical contrast by laser-induced phase changes: Real time optical measurement of fast transformation times

Abstract

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 structural transformations are induced by pulsed laser irradiation in micron-sized regions. A two beam configuration is used to follow the evolution of the optical properties of the films in real time. It is shown that real time optical measurements provide a unique tool to analyse laser-induced fast structural transformations leading to optical contrast. Processes occurring via relaxation, solid state crystallization or melting-solidification are clearly distinguished. From the analysis of the optical transients the minimum transformation times are directly determined. © 1992 Springer-Verlag.