Nonlinear all-dielectric nanoantenna reconfigured by electron-hole plasma

Interplay of magnetic and electric dipole moments of a single dielectric nanoparticle completely governs its scattering properties in the optical range. The amplitudes and phases of the induced dipoles can be altered by varying permittivity of the nanoparticle via generation of electron-hole plasma. In this work, we show ultrafast operation time of a silicon nanoantenna controlled by electron-hole plasma, allowing for ultrafast variation of the excited dipole moments. Basing on the experimental results, we develop an analytical model describing transient response of a silicon nanoparticle to an intense laser pulse and show theoretically that plasma induced optical nonlinearity leads to ultrafast reconfiguration of the scattering power pattern. Our work provides a strategy to design ultracompact and fast all-optical switches, which can be applied for broad range of nonlinear nanophotonic devices.