Antenna surface plasmon emission by inelastic tunneling

Cheng Zhang,Christophe Sauvan,Jean-Jacques Greffet,François Marquier,Anne-Lise Coutrot,Jean-Paul Hugonin

doi:10.1038/s41467-019-12866-3

Abstract

Surface plasmons polaritons are mixed electronic and electromagnetic waves. They have become a workhorse of nanophotonics because plasmonic modes can be confined in space at the nanometer scale and in time at the 10 fs scale. However, in practice, plasmonic modes are often excited using diffraction-limited beams. In order to take full advantage of their potential for sensing and information technology, it is necessary to develop a microscale ultrafast electrical source of surface plasmons. Here, we report the design, fabrication and characterization of nanoantennas to emit surface plasmons by inelastic electron tunneling. The antenna controls the emission spectrum, the emission polarization, and enhances the emission efficiency by more than three orders of magnitude. We introduce a theoretical model of the antenna in good agreement with the results.

Highlights

Surface plasmons polaritons are mixed electronic and electromagnetic waves
Surface plasmon polaritons (SPPs) are mixed electronic and electromagnetic modes propagating along the interface between a metal and a dielectric[1]
The source current density can be confined in a nanoantenna or in a metallic tip enabling electromagnetic excitation localized at the nanometer scale

Summary

Introduction

Surface plasmons polaritons are mixed electronic and electromagnetic waves. They have become a workhorse of nanophotonics because plasmonic modes can be confined in space at the nanometer scale and in time at the 10 fs scale. The source current density can be confined in a nanoantenna or in a metallic tip enabling electromagnetic excitation localized at the nanometer scale. Both photon[21] and plasmon[22,23,24] emission have been reported using scanning tunneling microscope (STM) tips. Spectral control of LEIT using resonant nanocubes has been demonstrated recently[44] only a small fraction of the tunneling current was affected by the antenna. These results demonstrate the potential of plasmonic nanoantennas to tailor LEIT. While it is known that a localized gap plasmon takes place between the tip and the surface, no control of this mode using antennas has been reported

Methods

Results

Conclusion