Overcoming the rate-directionality tradeoff: a room-temperature ultrabright quantum light source

TL;DR

This paper presents a hybrid nanophotonic device that significantly enhances the emission rate and directionality of room-temperature quantum dot single-photon sources, enabling ultra-fast quantum light applications.

Contribution

It introduces a novel monolithic photonic resonator combining a gold nanocone and circular Bragg antenna for simultaneous rate enhancement and emission directionality.

Findings

Achieved 20-fold emission rate enhancement.

Recorded high directionality with brightness increase up to 580 times.

Projected photon rates approaching 2.3×10^8 photons/sec.

Abstract

Deterministic GHz-rate single photon sources at room-temperature would be essential components for various quantum applications. However, both the slow intrinsic decay rate and the omnidirectional emission of typical quantum emitters are two obstacles towards achieving such a goal which are hard to overcome simultaneously. Here we solve this challenge by a hybrid approach, using a complex monolithic photonic resonator constructed of a gold nanocone responsible for the rate enhancement, and a circular Bragg antenna for emission directionality. A repeatable process accurately binds quantum dots to the tip of the antenna-embedded nanocone. As a result we achieve simultaneous 20-fold emission rate enhancement and record-high directionality leading to an increase in the observed brightness by a factor as large as 580 (120) into an NA = 0.22 (0.5). We project that such miniaturized on-chip devices can reach photon rates approaching 2.3*10^8 single photons/second thus enabling ultra-fast light-matter interfaces for quantum technologies at ambient conditions.