Post-selective two-photon interference from a continuous non-classical stream of photons emitted by a quantum dot

TL;DR

This paper demonstrates a semiconductor single-photon source emitting photons with high coherence, and uses post-selective two-photon interference to test photon indistinguishability, highlighting the impact of environmental fluctuations and detection improvements.

Contribution

It introduces a high-coherence, electrically driven quantum dot photon source and applies post-selective two-photon interference to evaluate photon indistinguishability.

Findings

Photon coherence time up to 400 ps under fixed bias

Increasing injection current reduces coherence time due to environmental fluctuations

Post-selective two-photon interference achieved with this source

Abstract

We report an electrically driven semiconductor single photon source capable of emitting photons with a coherence time of up to 400 ps under fixed bias. It is shown that increasing the injection current causes the coherence time to reduce and this effect is well explained by the fast modulation of a fluctuating environment. Hong-Ou-Mandel type two-photon interference using a Mach-Zehnder interferometer is demonstrated using this source to test the indistinguishability of individual photons by post-selecting events where two photons collide at a beamsplitter. Finally, we consider how improvements in our detection system can be used to achieve a higher interference visibility.