Scalable ion-photon quantum interface based on integrated diffractive mirrors

TL;DR

This paper presents a microfabricated ion trap with integrated diffractive mirrors that significantly improves photon collection efficiency, enabling scalable and fault-tolerant quantum networking with trapped ions.

Contribution

It introduces an integrated optical device that enhances ion-photon coupling efficiency, advancing scalable quantum networking technology.

Findings

Couples 4.1% of ion fluorescence into single mode fibre, nearly triple previous efficiencies.

Collects 5.8% of the ion's fluorescence with sub-wavelength resolution.

Couples 71% of collected light into the fibre, suitable for fault-tolerant quantum information processing.

Abstract

Quantum networking links quantum processors through remote entanglement for distributed quantum information processing (QIP) and secure long-range communication. Trapped ions are a leading QIP platform, having demonstrated universal small-scale processors and roadmaps for large-scale implementation. Overall rates of ion-photon entanglement generation, essential for remote trapped ion entanglement, are limited by coupling efficiency into single mode fibres5 and scaling to many ions. Here we show a microfabricated trap with integrated diffractive mirrors that couples 4.1(6)% of the fluorescence from a $^{174}$Yb$^+$ ion into a single mode fibre, nearly triple the demonstrated bulk optics efficiency. The integrated optic collects 5.8(8)% of the {\pi} transition fluorescence, images the ion with sub-wavelength resolution, and couples 71(5)% of the collected light into the fibre. Our technology is suitable for entangling multiple ions in parallel and overcomes mode quality limitations of existing integrated optical interconnects. In addition, the efficiencies are sufficient for fault tolerant QIP.