Nanosecond time-resolved reflectivity determination of the melting of metals upon pulsed laser annealing

Abstract

Thin metal films (Cu, Au, Ni) on quartz glass were illuminated with nanosecond pulses of a frequency doubled Nd:YAG laser ( λ=532 nm). The transient reflectivity behaviour was probed at the wavelength 633 nm, where these metals exhibit Drude-like optical behaviour: the reflectivity decreases with temperature in the solid and in the liquid state as well as at the solid–liquid phase transition. It is shown that nanosecond time-resolved reflectivity measurements can be used to determine the melting of these metal surfaces due to the reflectivity difference between the solid and the liquid phase.