Subwavelength asymmetric Au–VO ₂ nanodisk dimer for switchable directional scattering

Abstract

We propose an asymmetric Au-VO 2 nanodisk dimer for realizing a switchable directional scattering. Specifically, the directional scattering can be triggered on/off through controlling the phase transition of the VO 2 nanodisk from metallic to semiconductor state. More strikingly, an obvious directional scattering with the directivity of ∼ 40 dB is achieved under the metallic state of VO 2 nanodisk. This tunable directional scattering is further explained with an interference model where the Au and VO 2 nanodisks are treated as two weakly interacting electric dipoles. The phase transition controlled scattering patterns of asymmetric Au-VO 2 nanodisk dimer are then well interpreted from the phase difference between these two dipoles.