Electron-Fed Light Emitting Optical Gap Antennas

Our research consists at developing a new method for information processing based on the local transduction between electrons and photons with a nanoscale plasmonic light emitting optical antenna. This electron-fed component is an elementary transmission unit for interfacing an electronic control layer with a nanophotonic circuit. At the core of the device is an atomic-scale tunnel gap whereby photons and electrons can be reciprocally mixed.

The transduction mechanism results from the electron-plasmon interactions. Upon injection of electrical charges in the device, localized light emission is observed in the feedgap of the optical antenna (see Fig. 1). Light emission is usually understood as the inelastic energy transfer of a tunneling electron into a radiative plasmon. In this framework, the energy hν of the photons is bound by the applied bias eV. For tunneling gap antennas sustaining a large current density we demonstrate that other emission mechanisms are at play. The emission spectra unambiguously show that the photon energy can exceed the quantum limit imposed by the bias for one-electron process. By introducing electron-electron interaction within a hot distribution of carriers, we correctly reproduce the experimental data. Our results indicate that a process involving up to 3 electrons dictates the high-energy side of the emission spectrum. We further experimentally show that the electron temperature is reduced when the electrons couple their energy to radiative surface plasmons.

Our approach based upon tunneling optical antenna enables a transduction between electrons and photons with a metal-based component. This is the first step requires for designing transponding units based on electrically-controlled optical antennas.

The research leading to these results has received funding from the European Research Council under the European Community’s Seventh Framework Program FP7/2007-2013 Grant Agreement no 306772.

Figure 1: Electron-fed light emitting optical gap antenna

mickael.buret@u-bourgogne.fr