Imaging trapped ions with a microfabricated lens for quantum information processing

TL;DR

This paper demonstrates the first imaging of trapped ions using a microfabricated in-vacuum phase Fresnel lens, achieving a collection efficiency suitable for scalable quantum information processing, and offering an integrated optical solution for large-scale QIP.

Contribution

It introduces a microfabricated in-vacuum PFL for ion imaging, enabling scalable, high-efficiency optical coupling in trapped-ion quantum computing architectures.

Findings

Achieved 4.2% ion fluorescence collection efficiency.

Demonstrated a contrast ratio of 23 between ion signal and background.

Measured a depth of focus of 19.4 μm and a field of view of 140 μm.

Abstract

Trapped ions are a leading system for realizing quantum information processing (QIP). Most of the technologies required for implementing large-scale trapped-ion QIP have been demonstrated, with one key exception: a massively parallel ion-photon interconnect. Arrays of microfabricated phase Fresnel lenses (PFL) are a promising interconnect solution that is readily integrated with ion trap arrays for large-scale QIP. Here we show the first imaging of trapped ions with a microfabricated in-vacuum PFL, demonstrating performance suitable for scalable QIP. A single ion fluorescence collection efficiency of 4.2 +/- 1.5% was observed, in agreement with the previously measured optical performance of the PFL. The contrast ratio between the ion signal and the background scatter was 23 +/- 4. The depth of focus for the imaging system was 19.4 +/- 2.4 {\mu}m and the field of view was 140 +/- 20 {\mu}m. Our approach also provides an integrated solution for high-efficiency optical coupling in neutral atom and solid state QIP architectures.