Frequency Feedback for Two-Photon Interference from Separate Quantum Dots

TL;DR

This paper demonstrates active frequency feedback stabilization of photons from separate quantum dots, enabling high-visibility quantum interference crucial for quantum networks.

Contribution

It introduces a novel feedback method using a rubidium-based Faraday filter to stabilize photon frequencies from separate quantum dots.

Findings

Frequency stabilization to less than 1.5% of emission linewidth

Hong-Ou-Mandel interference with 41% visibility

Potential for scalable quantum networks

Abstract

We employ active feedback to stabilize the frequency of single photons emitted by two separate quantum dots to an atomic standard. The transmission of a single, rubidium-based Faraday filter serves as the error signal for frequency stabilization to less than 1.5% of the emission linewidth. Long-term stability is demonstrated by Hong-Ou-Mandel interference between photons from the two quantum dots. The observed visibility of $V_{\mathrm{lock}}=(41 \pm 5)$% is limited only by internal dephasing of the dots. Our approach facilitates quantum networks with indistinguishable photons from distributed emitters.