Optical coherence and hyperfine structure of the 7F0-5D0 transition in EuCaWO4

TL;DR

This study investigates the optical and hyperfine properties of Eu3+ ions in CaWO4 crystals at low temperature, revealing multiple environments and hyperfine structures, with implications for quantum memory technologies.

Contribution

It provides detailed spectroscopic characterization of Eu3+:CaWO4, including hyperfine structures and coherence properties, which were previously unexplored in this material.

Findings

Identified four distinct Eu3+ environments in CaWO4 at 3 K

Resolved hyperfine structures in ground and excited states

Measured optical coherence and lifetime properties

Abstract

Rare-earth ions doped in crystals with low nuclear-spin densities are highly promising candidates for quantum technology applications. In this study, we investigated the spectroscopic properties of the 7F0 - 5 D0 optical and the hyperfine transitions of Eu3+ ions in a CaWO4 crystal, where the nuclear spin arises solely from the 183W isotope, with a natural abundance of 14%. At a temperature of 3 K, we experimentally identified four distinct crystal field environments for Eu3+ ions in a 0.1 at.% Eu3+ doped CaWO4 crystal. The optical coherence properties of Eu3+ ions in these environments were characterized. Additionally, we resolved the hyperfine structures in the 7F0 ground state and 5D0 excited state, and determined the 7F0 ground state lifetimes using spectral hole-burning techniques. These findings highlight the significant potential of Eu3+:CaWO4 for optical quantum memory applications.