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

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.