Abstract

Numerous investigations of the mechanisms for pulsed laser-induced phase transition provide ample evidence that the surface of metals and semiconductors undergoes a solid-liquid phase change as soon as a critical laser fluence is exceeded. There is no doubt about the thermal nature of the phase transition as long as nanosecond pulses are being used [1]. It is the main purpose of this contribution to clarify whether under picosecond irradiation the simple thermal melting approach is still valid. This question is focused on the time required to establish thermal equilibrium between carriers and phonons [2]. Specific attention is paid to the quantitative measurements of plasma density and lattice temperature developed during and after the excitation with picosecond laser pulses.

© 1984 Optical Society of America