An integrated whispering-gallery-mode resonator for solid-state coherent quantum photonics

TL;DR

This paper presents an integrated microdisk cavity with quantum dots that enables coherent photon routing and scattering, advancing solid-state quantum photonic devices.

Contribution

It demonstrates a novel integrated resonator system with measurable Purcell enhancement for coherent photon control in quantum photonics.

Findings

Purcell factor of 6.9±0.9 observed

Coherent photon routing demonstrated

Single-photon nonlinearity achieved

Abstract

Tailored photonic cavities allow enhancing light-matter interaction ultimately to create a fully coherent quantum interface. Here, we report on an integrated microdisk cavity containing self-assembled quantum dots to coherently route photons between different access waveguides. We measure a Purcell factor of $F_{exp}=6.9\pm0.9$ for a cavity quality factor of about 10,000, allowing us to observe clear signatures of coherent scattering of photons by the quantum dots. We show how this integrated system can coherently re-route photons between the drop and bus ports, and how this routing is controlled by detuning the quantum dot and resonator, or through the strength of the excitation beam, where a critical photon number less than one photon per lifetime is required. We discuss the strengths and limitations of this approach, focusing on how the coherent scattering and single-photon nonlinearity can be used to increase the efficiency of quantum devices such as routers or Bell-state analyzers.