Picosecond Laser Induced Melting: The Dielectric Function of Molten Silicon and Superheating in the Liquid Phase

Abstract

ABSTRACTThe complex dielectric function of molten silicon produced after picosecond illumination is found to be well described by a Drude model from 1.1 eV to 3.5 eV. Close to the melting temperature, we obtain ωp = 2.50 1016rad/s and τ = 212 10−18s. Transiently, the liquid temperature can exceed the melting temperature or even the boiling temperature Tb. We observe this transient heating and model it with a relatively simple computer code which includes superheating of the liquid above Tb. These measurements are possible thanks to a novel pump and probe technique.