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

We present Purcell-enhanced $F_P>25$ semiconductor InAs quantum dot decay times of T₁<30 ps, enabled by deterministic hybrid circular Bragg gratings (hCBGs). We investigate the benefits of these short T₁ 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.