Ion Trap with In-Vacuum High Numerical Aperture Imaging for a Dual-Species Modular Quantum Computer

TL;DR

This paper introduces an advanced ion trap system with in-vacuum high numerical aperture lenses that significantly improves photon collection efficiency, facilitating faster entanglement generation for scalable quantum computing and networking.

Contribution

The work demonstrates the highest free-space photon collection efficiency in an ion trap using in-vacuum lenses with a numerical aperture of 0.8, enabling more efficient quantum networking.

Findings

Achieved 10% photon collection efficiency from a $^{138}$Ba$^+$ ion.

Mitigated effects of lenses on ion position and motion.

Enhanced entanglement generation rate for quantum networks.

Abstract

Photonic interconnects between quantum systems will play a central role in both scalable quantum computing and quantum networking. Entanglement of remote qubits via photons has been demonstrated in many platforms; however, improving the rate of entanglement generation will be instrumental for integrating photonic links into modular quantum computers. We present an ion trap system that has the highest reported free-space photon collection efficiency for quantum networking. We use a pair of in-vacuum aspheric lenses, each with a numerical aperture of 0.8, to couple 10% of the 493 nm photons emitted from a $^{138}$Ba$^+$ ion into single-mode fibers. We also demonstrate that proximal effects of the lenses on the ion position and motion can be mitigated.