Optical modulation of surface plasmon-polariton coupling in a gallium/aluminium composite

We report on the use of a reversible nanoscale light-induced structural transformation in a new type of gallium/aluminium composite material interfaced with a dielectric to control the efficiency with which light is coupled to a surface plasmon-polariton wave at the interface, and thereby to modulate the optical reflectivity of the interface. An optical fluence of just a few mJ/cm2 is sufficient to significantly modulate the composite’s dielectric properties and thus to provide high-contrast nonlinear optical and plasmonic switching functionality on a nano- to microsecond timescale, for signals in the visible and near infrared wavelength ranges.