Near-Field Resonance at Far-Field Anti-Resonance: Plasmonically Enhanced Light Emission with Minimum Scattering Nanoantennas

TL;DR

This paper reveals a phenomenon where plasmonic nanoantenna arrays exhibit a near-field resonance with minimal far-field scattering, enabling narrowband light emission enhancement from quantum dots.

Contribution

It introduces the concept of near-field resonance at far-field anti-resonance in plasmonic arrays, demonstrating minimal scattering with enhanced emission.

Findings

Narrow bandwidth emission enhancement observed from quantum dots.

Anti-crossing in far-field energies and crossing in near-field energies.

Standing quadrupolar wave explains the dark collective resonance.

Abstract

We demonstrate that a periodic array of optical antennas sustains a resonant Near-Field (NF) and an anti-resonant Far-Field (FF) at the same energy and in-plane momentum. This phenomenon arises in the context of coupled plasmonic lattice resonances, whose bright and dark character is interchanged at a critical antenna length. The energies of these modes anti-cross in the FF, but cross in the NF. Hence, we observe an extremely narrow bandwidth emission enhancement from quantum dots in the proximity of the array, while the antennas scatter minimally into the FF. Simulations reveal that a standing wave with a quadrupolar field distribution is the origin of this dark collective resonance.