# Coherent control and single-shot readout of a rare-earth ion embedded in a nanophotonic cavity

## TL;DR

This paper demonstrates the coherent control and high-fidelity single-shot readout of single ytterbium ions in a nanophotonic cavity, advancing solid-state quantum network components with long coherence times and efficient optical interfaces.

## Contribution

It introduces a platform using single 1Yb^{3+} ions in yttrium orthovanadate coupled to nanophotonic cavities, achieving long coherence times and high-fidelity readout, which is novel for quantum network applications.

## Key findings

- Optical linewidths less than 1 MHz for cavity-coupled ions
- Spin coherence times exceeding 30 ms
- Single-shot readout fidelity over 95%

## Abstract

Quantum networks based on optically addressable spin qubits promise to enable secure communication, distributed quantum computing, and tests of fundamental physics. Scaling up quantum networks based on solid-state luminescent centers requires coherent spin and optical transitions coupled to photonic resonators. Here we investigate single $\mathrm{{}^{171}Yb^{3+}}$ ions in yttrium orthovanadate coupled to a nanophotonic cavity. These ions possess optical and spin transitions that are first-order insensitive to magnetic field fluctuations, enabling optical linewidths less than 1 MHz and spin coherence times exceeding 30 ms for cavity-coupled ions. The cavity-enhanced optical emission rate facilitates efficient spin initialization and conditional single-shot readout with fidelity greater than 95%. These results showcase a solid-state platform based on single coherent rare-earth ions for the future quantum internet.