Multi-slot optical Yagi-Uda antenna for efficient unidirectional radiation to free space

TL;DR

This paper introduces a novel multi-slot optical Yagi-Uda antenna based on plasmonic nanoantennas, demonstrating highly unidirectional radiation and potential for integrated optical energy transfer.

Contribution

It presents the design and demonstration of a magnetic-dipole-fed multi-slot optical Yagi-Uda antenna, a new type of nanoantenna with unidirectional radiation capabilities.

Findings

Achieves highly unidirectional radiation to free space.

Demonstrates phase engineering of surface plasmon polaritons.

Provides potential for integrated optical energy transfer.

Abstract

Plasmonic nanoantennas are key elements in nanophotonics capable of directing radiation or enhancing the transition rate of a quantum emitter. Slot-type magnetic-dipole nanoantennas, which are complementary structures of typical electric-dipole-type antennas, have received little attention, leaving their antenna properties largely unexplored. Here we present a novel magnetic-dipole-fed multi-slot optical Yagi-Uda antenna. By engineering the relative phase of the interacting surface plasmon polaritons between the slot elements, we demonstrate that the optical antenna exhibits highly unidirectional radiation to free space. The unique features of the slot-based magnetic nanoantenna provide a new possibility of achieving integrated features such as energy transfer from one waveguide to another by working as a future optical via.