On-chip resonantly-driven quantum emitter with enhanced coherence

TL;DR

This paper demonstrates on-chip quantum dot resonance fluorescence with enhanced photon coherence, enabling scalable integrated quantum-optical devices for quantum information processing.

Contribution

It introduces a method to implement resonantly-driven quantum dot fluorescence on-chip with minimal laser background, improving photon coherence for quantum photonic circuits.

Findings

On-chip quantum dot RF with negligible laser background

Enhanced photon coherence compared to off-resonant excitation

Potential for scalable integrated quantum-optical devices

Abstract

Advances in nanotechnology provide techniques for the realisation of integrated quantum-optical circuits for on-chip quantum information processing(QIP). The indistinguishable single photons, required for such devices can be generated by parametric down-conversion, or from quantum emitters such as colour centres and quantum dots(QDs). Among these, semiconductor QDs offer distinctive capabilities including on-demand operation, coherent control, frequency tuning and compatibility with semiconductor nanotechnology. Moreover, the coherence of QD photons can be significantly enhanced in resonance fluorescence(RF) approaching at its best the coherence of the excitation laser. However, the implementation of QD RF in scalable on-chip geometries remains challenging due to the need to suppress stray laser photons. Here we report on-chip QD RF coupled into a single-mode waveguide with negligible resonant laser background and show that the coherence is enhanced compared to off-resonant excitation. The results pave the way to a novel class of integrated quantum-optical devices for on-chip QIP with embedded resonantly-driven quantum emitters.