Optical switching at ZnSe-Ga interfaces via nanoscale light-induced metallisation

A structural transformation induced by optical impulse excitation of only a few mJ/cm2 fluence affecting the nanoscale surface melt layer of gallium at a ZnSe-gallium interface leads to a fast, substantial and fully reversible change in reflectivity of up to 50%. Recovery occurs within a few μs after excitation is withdrawn and less than 1 μs at temperatures more than 4 K below gallium's melting point.