Simultaneous anti-bunched and super-bunched photons from a GaAs Quantum dot in a dielectric metasurface

TL;DR

This paper demonstrates a dielectric metasurface that enhances emission from a GaAs quantum dot, enabling simultaneous generation of anti-bunched and super-bunched photons, which could advance quantum information protocols.

Contribution

The study introduces a dielectric Mie-resonant metasurface that boosts both neutral and charged exciton emissions from a single quantum dot, enabling dual-mode quantum light emission.

Findings

Enhanced photoluminescence across excitonic transitions by an order of magnitude.

Achieved anti-bunched and super-bunched photon emission from the same quantum dot.

Super-bunching depends on spectral overlap with Mie resonances.

Abstract

Semiconductor quantum dots host a rich manifold of excitonic complexes, including neutral excitons that emit anti-bunched single photons and charged exciton complexes capable of producing super-bunched photons via cascade emission. Accessing both emission regimes from a single emitter would open routes to novel quantum protocols, including advanced quantum imaging. In practice, however, emission from charged exciton complexes is intrinsically weak, often orders of magnitude dimmer than neutral excitons, placing simultaneous dual-mode operation out of reach. Here, we overcome this limitation by embedding the quantum dot in a dielectric Mie-resonant metasurface that provides order-of-magnitude photoluminescence enhancement across both neutral and charged exciton transitions of a single GaAs quantum dot. Under identical non-resonant pumping conditions, the emission from the neutral exciton yields anti-bunched emission ($g^{(2)}(0) < 0.5$) and the emission from positively charged exciton complexes shows super-bunched emission ($g^{(2)}(0) > 3.5$) with comparable count rates (~12 kHz). Crucially, super-bunching emerges only when charged exciton emission spectrally overlaps with the Mie resonances and vanishes in un-patterned slabs, demonstrating that photonic engineering, is essential for accessing these weak quantum light states. These results demonstrate a scalable, position-tolerant platform for harnessing the full excitonic structure of solid-state emitters.