Hyperfine characterization and coherence lifetime extension in Pr3+:La2(WO4)3

TL;DR

This study characterizes the hyperfine interactions in Pr3+:La2(WO4)3 and demonstrates a significant extension of spin coherence lifetime, enhancing its potential for quantum memory applications.

Contribution

It provides detailed hyperfine interaction parameters and shows a nearly three-order increase in coherence lifetime through magnetic field optimization.

Findings

Hyperfine interaction parameters characterized for ground and excited states.

Spin coherence lifetime extended to 158 ms in optimized magnetic field.

Potential for improved quantum memory performance demonstrated.

Abstract

Rare-earth ions in dielectric crystals are interesting candidates for storing quantum states of photons. A limiting factor on the optical density and thus the conversion efficiency is the distortion introduced in the crystal by doping elements of one type into a crystal matrix of another type. Here, we investigate the system Pr3+:La2(WO4)3, where the similarity of the ionic radii of Pr and La minimizes distortions due to doping. We characterize the praseodymium hyperfine interaction of the ground state (3H4) and one excited state (1D2) and determine the spin Hamiltonian parameters by numerical analysis of Raman-heterodyne spectra, which were collected for a range of static external magnetic field strengths and orientations. On the basis of a crystal field analysis, we discuss the physical origin of the experimentally determined quadrupole and Zeeman tensor characteristics. We show the potential for quantum memory applications by measuring the spin coherence lifetime in a magnetic field that is chosen such that additional magnetic fields do not shift the transition frequency in first order. Experimental results demonstrate a spin coherence lifetime of 158 ms - almost three orders of magnitude longer than in zero field.