Interference of Single Photons from Two Separate Semiconductor Quantum Dots

TL;DR

This paper demonstrates quantum interference between photons emitted by two separate semiconductor quantum dots, showing partial photon coalescence and the effects of dephasing and detection timing.

Contribution

It presents the first experimental observation of interference between photons from separate quantum dots with tunable energies, highlighting the impact of dephasing and detection timing.

Findings

Total coalescence probability of 18.1%

Post-selected coalescence probability of 47%

Coincidence rate below classical limit

Abstract

We demonstrate and characterize interference between discrete photons emitted by two separate semiconductor quantum dot states in different samples excited by a pulsed laser. Their energies are tuned into resonance using strain. The photons have a total coalescence probability of 18.1% and the coincidence rate is below the classical limit. Post-selection of coincidences within a narrow time window increases the coalescence probability to 47%. The probabilities are reduced from unity because of dephasing and the postselection value is also reduced by the detector time response.