STM-based electrical generation of surface plasmons enhanced by nanoantenna

Surface plasmons polaritons (SPP) are charge-density surface waves, confined at the interface between a metal and an insulator. This confinement property makes SPPs good candidates for optoelectronic devices miniaturization. Recently, several groups have used a scanning tunneling microscope (STM) tip [1], [2] to generate surface plasmons via inelastic tunneling. This elegant technique suggests the possibility to integrate an electrical SPP source directly into the SPP circuit. Yet, the efficiency is very low and the radiation spectrum is very large. We introduce a resonant plasmonic nanoantenna to circumvent these issues. Our study predicts an enhancement by more than two orders of magnitude of the electrical power conversion to SPP as well as a tunable narrow emission spectrum. Our analysis allows one to understand recent experiments from other groups demonstrating such an enhancement [3], [4], [5]. Some of those results were recently published in [6].