Two-photon interference from a quantum dot--microcavity: Persistent pure-dephasing and suppression of time-jitter

TL;DR

This study demonstrates highly indistinguishable photon emission from a quantum dot-microcavity system, revealing pure-dephasing as the main imperfection source and showing how temperature tuning enhances interference visibility.

Contribution

It provides new insights into the effects of pure-dephasing versus time-jitter in quantum dot photon sources and demonstrates improved photon indistinguishability through cavity resonance tuning.

Findings

Over 80% Hong–Ou–Mandel interference visibility at spectral resonance.

Pure-dephasing identified as the main source of photon indistinguishability degradation.

Temperature tuning allows control over quantum dot-cavity detuning and photon emission properties.

Abstract

We demonstrate the emission of highly indistinguishable photons from a quasi-resonantly pumped coupled quantum dot--microcavity system operating in the regime of cavity quantum electrodynamics. Changing the sample temperature allows us to vary the quantum dot--cavity detuning, and on spectral resonance we observe a three-fold improvement in the Hong--Ou--Mandel interference visibility, reaching values in excess of 80\%. Our measurements off-resonance allow us to investigate varying Purcell enhancements, and to probe the dephasing environment at different temperatures and energy scales. By comparison with our microscopic model, we are able to identify pure-dephasing and not time-jitter as the dominating source of imperfections in our system.