# Optical and spin properties of a single praseodymium ion in a crystal

## TL;DR

This paper explores the optical and spin characteristics of individual praseodymium ions in YAG crystals at cryogenic temperatures, demonstrating stable photoluminescence and nuclear spin detection with implications for quantum technologies.

## Contribution

It presents the first detailed study of single praseodymium ions' optical and spin properties, including hyperfine structure and coherence times, using novel detection techniques.

## Key findings

- Single praseodymium ions exhibit stable photoluminescence with hyperfine splitting.
- Nuclear spins are detected via optical upconversion readout.
- Spin coherence is limited by spin-phonon interactions at low temperatures.

## Abstract

The investigation of single atoms in solids, with both optical and nuclear spin access is of particularly interest with applications ranging from nanoscale sensing to quantum computation. Here, we study the optical and spin properties of single praseodymium ions in an yttrium aluminum garnet (YAG) crystal at cryogenic temperature. The single nuclear spin of single praseodymium ions is detected through a background-free optical upconverting readout technique. Single ions show stable photoluminescence (PLE) with spectrally resolved hyperfine splitting of the praseodymium ground state. Based on this measurement, optical Rabi and optically detected magnetic resonance (ODMR) measurements are performed to study the spin coherence properties. Our results reveal that the spin coherence time of single praseodymium nuclear spins is limited by the strong spin-phonon coupling at experimental temperature.