Proposal for a Tunable Room‐Temperature Single‐Photon Source Based on a Plasmonic Nanoantenna Driven by Inelastic Tunneling in the Coulomb Regime

Abstract

Herein, a tunnel‐current‐driven plasmonic nanoantenna for the generation of single photons is proposed. The proposal uses two constituents: 1) small gold nanoparticles that feature Coulomb blockade already at room temperature combined with an 2) self‐similar nanorod arrangement. The Coulomb blockade allows for single‐plasmon generation and the nanorod arrangement for an efficient transformation into photons. As the emission from such an electrically driven antenna follows its spectral scattering response, the color of single photons can be tuned by geometrical changes of the antenna over an extremely broad range far into the infrared. The calculations suggest high photon purities, repetition rates beyond, and efficiencies comparable to ordinary single‐photon sources based on emitters like color centers or heralded single‐photon sources, respectively. Given recent achievements in the field and the simplicity of the proposal, the device can be built with existing technology.