On-demand semiconductor single-photon source with near-unity indistinguishability

TL;DR

This paper demonstrates a highly efficient, indistinguishable single-photon source using semiconductor quantum dots under pulsed resonance fluorescence, achieving near-unity indistinguishability suitable for quantum computing.

Contribution

It presents the first on-demand, pulsed resonance fluorescence single-photon source with near-unity indistinguishability from a semiconductor quantum dot.

Findings

Hong-Ou-Mandel interference visibility of 0.97(2)

Less than 0.3% background contributions in photon generation

Successful implementation of a high-fidelity quantum CNOT gate

Abstract

Single photon sources based on semiconductor quantum dots offer distinct advantages for quantum information, including a scalable solid-state platform, ultrabrightness, and interconnectivity with matter qubits. A key prerequisite for their use in optical quantum computing and solid-state networks is a high level of efficiency and indistinguishability. Pulsed resonance fluorescence (RF) has been anticipated as the optimum condition for the deterministic generation of high-quality photons with vanishing effects of dephasing. Here, we generate pulsed RF single photons on demand from a single, microcavity-embedded quantum dot under s-shell excitation with 3-ps laser pulses. The pi-pulse excited RF photons have less than 0.3% background contributions and a vanishing two-photon emission probability. Non-postselective Hong-Ou-Mandel interference between two successively emitted photons is observed with a visibility of 0.97(2), comparable to trapped atoms and ions. Two single photons are further used to implement a high-fidelity quantum controlled-NOT gate.