Electrically-driven Yagi-Uda antennas for light

René Kullock,Philipp Grimm,Bert Hecht,Monika Emmerling,Maximilian Ochs

doi:10.1038/s41467-019-14011-6

Abstract

Yagi-Uda antennas are a key technology for efficiently transmitting information from point to point using radio waves. Since higher frequencies allow higher bandwidths and smaller footprints, a strong incentive exists to shrink Yagi-Uda antennas down to the optical regime. Here we demonstrate electrically-driven Yagi-Uda antennas for light with wavelength-scale footprints that exhibit large directionalities with forward-to-backward ratios of up to 9.1 dB. Light generation is achieved via antenna-enhanced inelastic tunneling of electrons over the antenna feed gap. We obtain reproducible tunnel gaps by means of feedback-controlled dielectrophoresis, which precisely places single surface-passivated gold nanoparticles in the antenna gap. The resulting antennas perform equivalent to radio-frequency antennas and combined with waveguiding layers even outperform RF designs. This work paves the way for optical on-chip data communication that is not restricted by Joule heating but also for advanced light management in nanoscale sensing and metrology as well as light emitting devices.

Highlights

Yagi-Uda antennas are a key technology for efficiently transmitting information from point to point using radio waves
The resulting devices represent an efficient link between electron-based integrated computer chips and photonbased fiber networks and in particular enable on-chip optical data communication because antennas outperform subwavelength waveguides for longer distances[1], allow for multiple beam crossings, have an adaptable footprint and are not restricted by Joule heating[2,3]
Generating light locally at the nanoscale is possible by different means, for example via scanning tunneling microscopes (STMs)[13,14], carbon nanotubes[15,16,17,18], quantum dots[19] and optical antennas[20,21,22]

Summary

Introduction

Yagi-Uda antennas are a key technology for efficiently transmitting information from point to point using radio waves. 1234567890():,; Yagi-Uda antennas consisting of a reflector, an active feed element and directors are a brilliant source of radiation as they allow locally generated electromagnetic fields to be emitted in a specific direction by means of interference effects (see Fig. 1). Obtaining directed electrically driven emission is only possible by utilizing STMs23,24, which again involves bulky lab-scale setups, or by twisting the arms of electrically driven dipole antennas in order to break the point symmetry[25] The latter show a limited geometrical definition and directionality only, are by design not scalable to significantly higher values and, not suitable for, e.g., cross-talk free on-chip data communication. Particle Tunnel gap Antenna x management in nanoscale sensing and metrology as well as lightemitting devices

Methods

Results

Conclusion