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

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