Femtosecond laser amorphization of tellurium

Abstract

Polycrystalline tellurium becomes amorphous after irradiation with strong femtosecond pulses. The amorphization is sensitive to the initial temperature but not very sensitive to the temporal profile of the optical excitation. Above the amorphization threshold, single-shot transient reflectivity traces show clear coherent phonon oscillations within 1 ps. These results suggest that amorphization is due to thermal melting rather than nonthermal melting or switching for pump fluences up to the ablation threshold.