High Purcell-enhancement in quantum-dot hybrid circular Bragg grating cavities for GHz-clockrate generation of indistinguishable photons

TL;DR

This paper demonstrates Purcell-enhanced quantum dot cavities that produce highly indistinguishable photons at GHz repetition rates, suitable for quantum information applications.

Contribution

It introduces hybrid circular Bragg grating cavities achieving Purcell factors over 25, enabling GHz-rate photon emission with high indistinguishability.

Findings

Purcell factor >25 achieved in quantum dot cavities

Photon indistinguishability of ≥96% at 12.5 ns delay

Repetition rates up to 1.28 GHz demonstrated

Abstract

We present Purcell-enhanced ($F_\mathrm{P}>25$) semiconductor InAs quantum dot decay times of $T_1<30\,$ps, enabled by deterministic hybrid circular Bragg gratings (hCBGs). We investigate the benefits of these short $T_1$ times on the two-photon indistinguishability for quasi-resonant and strictly resonant excitation, and observe visibilities $\geq96\%$ at 12.5$\,$ns time delay of consecutively emitted photons. The strongly Purcell-enhanced decay times enable a high degree of indistinguishability for elevated temperatures of up to 30$\,$K, and moreover, allow for excitation of up to 1.28$\,$GHz repetition rate. Our work highlights the prospects of high Purcell-enhanced solid-state quantum emitters for applications in quantum information and technologies operating at GHz clock-rates.