SearcharxivSearch

arXiv subjects

P. Petropoulos

Publications and source records attributed to P. Petropoulos.

4 recordsLinked to original sources

On the origin of the optical nonlinearity of a gallium-silica interface

Simultaneous measurements of the intensity and phase of a probe wave reflected from an interface between silica and elemental alpha-gallium reveal its very strong optical nonlinearity, affecting both these parameters of the reflected wave. The data corroborate with a non-thermal mechanism of optical response which assumes appearance of a homogeneous highly metallic layer, only a few nanometer thick, between the silica and bulk alpha-gallium.

physics.optics

Nanosecond dynamics of a gallium mirror's light-induced reflectivity change

Transient pump-probe optical reflectivity measurements of the nano/microsecond dynamics of a fully reversible, light-induced, surface-assisted metallization of gallium interfaced with silica are reported. The metallization leads to a considerable increase in the interface's reflectivity when solid a-gallium is on the verge of melting. The reflectivity change was found to be a cumulative effect that grows with light intensity and pulse duration. The reflectivity relaxes back to that of alpha-gallium when the excitation is withdrawn in a time that increases critically at gallium's melting point. The effect is attributed to a non-thermal light-induced structural phase transition.

physics.optics