Bright Purcell enhanced single-photon source in the telecom O-band based on a quantum dot in a circular Bragg grating

TL;DR

This paper demonstrates a bright, Purcell-enhanced single-photon source in the telecom O-band using a quantum dot coupled to a circular Bragg grating cavity, achieving high brightness, purity, and efficiency at 77K.

Contribution

It introduces a novel integration of quantum dots with circular Bragg gratings in the telecom O-band, achieving significant Purcell enhancement and high-quality single-photon emission.

Findings

Purcell enhancement of 4 achieved

End-to-end brightness of 1.4% and 23% at the first lens

Single-photon purity g(2)(0) = 0.01 at saturation

Abstract

The combination of semiconductor quantum dots (QDs) with photonic cavities is a promising way to realize non-classical light sources with state-of-the-art performances in terms of brightness, indistinguishability and repetition rate. In the present work we demonstrate the coupling of an InGaAs/GaAs QDs emitting in the telecom O-band to a circular Bragg grating cavity. We demonstrate a broadband geometric extraction efficiency enhancement by investigating two emission lines under above-band excitation, inside and detuned from the cavity mode, respectively. In the first case, a Purcell enhancement of 4 is attained. For the latter case, an end-to-end brightness of 1.4% with a brightness at the first lens of 23% is achieved. Using p-shell pumping, a combination of high count rate with pure single-photon emission (g(2)(0) = 0.01 in saturation) is achieved. Finally a good single-photon purity (g(2)(0) = 0.13) together with a high detector count rate of 191kcps is demonstrated for a temperature of up to 77K.