Fundamental limitations in spontaneous emission rate of single-photon sources

TL;DR

This paper develops an analytical model to compare single-photon emission enhancement in dielectric and plasmonic resonant structures, revealing that plasmonic nanostructures can significantly boost emission rates despite high losses.

Contribution

It introduces a transparent analytical model for single-photon emission in resonant structures, demonstrating plasmonic nanostructures can enhance emission rates two orders of magnitude over dielectric ones.

Findings

Plasmonic nanostructures can enhance emission rates despite high absorption.

External emission rate can be increased two orders of magnitude with plasmonics.

Guidelines for designing new plasmonic quantum emitters are provided.

Abstract

Rate of single-photon generation by quantum emitters (QEs) can be enhanced by placing a QE inside a resonant structure. This structure can represent an all-dielectric micro-resonator or waveguide and thus be characterized by ultra-low loss and dimensions on the order of wavelength. Or it can be a metal nanostructure supporting localized or propagating surface plasmon-polariton modes that are of subwavelength dimensions, but suffer from strong absorption. In this work, we develop a physically transparent analytical model of single-photon emission in resonant structures and show unambiguously that, notwithstanding the inherently high loss, the external emission rate can be enhanced with plasmonic nanostructures by two orders of magnitude compared to all-dielectric structures. Our analysis provides guidelines for developments of new plasmonic configurations and materials to be exploited in quantum plasmonics.