Characterization of ${}^{171}Yb^{3+}\!:\! YVO_4$ for photonic quantum technologies

TL;DR

This study characterizes the optical and spin properties of ${}^{171}Yb^{3+}$:YVO$_4$ crystals, revealing their potential for quantum interfaces due to narrow linewidths, large optical absorption, and coherent control capabilities.

Contribution

The paper provides detailed measurements of ${}^{171}Yb^{3+}$:YVO$_4$'s energy levels and coherence properties, highlighting its suitability for quantum technology applications.

Findings

Optical linewidths less than 3 kHz

Nuclear spin linewidths less than 50 Hz

Large optical absorption due to narrow inhomogeneous broadening

Abstract

Rare-earth ions in crystals are a proven solid-state platform for quantum technologies in the ensemble regime and attractive for new opportunities at the single ion level. Among the trivalent rare earths, ${}^{171}\mathrm{Yb}^{3+}$ is unique in that it possesses a single 4f excited-state manifold and is the only paramagnetic isotope with a nuclear spin of 1/2. In this work, we present measurements of the optical and spin properties of $^{171}$Yb$^{3+}$:YVO$_4$ to assess whether this distinct energy level structure can be harnessed for quantum interfaces. The material was found to possess large optical absorption compared to other rare-earth-doped crystals owing to the combination of narrow inhomogeneous broadening and a large transition oscillator strength. In moderate magnetic fields, we measure optical linewidths less than 3 kHz and nuclear spin linewidths less than 50 Hz. We characterize the excited-state hyperfine and Zeeman interactions in this system, which enables the engineering of a $\Lambda$-system and demonstration of all-optical coherent control over the nuclear spin ensemble. Given these properties, $^{171}$Yb$^{3+}$:YVO$_4$ has significant potential for building quantum interfaces such as ensemble-based memories, microwave-to-optical transducers, and optically addressable single rare-earth-ion spin qubits.