High-resolution spectroscopy of single Pr$^{3+}$ ions on the $^3$H$_4$-$^1$D$_2$ transition

TL;DR

This paper reports high-resolution spectroscopy of single Pr$^{3+}$ ions on a specific transition, revealing hyperfine structures and polarization effects, advancing quantum information applications in solid-state systems.

Contribution

The study extends previous work by exploring the $^3$H$_4$-$^1$D$_2$ transition at 606 nm and provides detailed measurements of autocorrelation, lifetime, spectra, and polarization dependencies of single ions.

Findings

Resolved hyperfine levels of the excited state.

Achieved narrower spectral lines through crystallite selection.

Provided comprehensive data on autocorrelation, lifetime, and emission spectra.

Abstract

Rare earth ions in crystals exhibit narrow spectral features and hyperfine-split ground states with exceptionally long coherence times. These features make them ideal platforms for quantum information processing in the solid state. Recently, we reported on the first high-resolution spectroscopy of single Pr$^{3+}$ ions in yttrium orthosilicate (YSO) nanocrystals. While in that work we examined the less explored $^3$H$_4$-$^3$P$_0$ transition at a wavelength of 488 nm, here we extend our investigations to the $^3$H$_4$-$^1$D$_2$ transition at 606 nm. In addition, we present measurements of the second-order autocorrelation function, fluorescence lifetime, and emission spectra of single ions as well as their polarization dependencies on both transitions; these data were not within the reach of the first experiments reported earlier. Furthermore, we show that by a proper choice of the crystallite, one can obtain narrower spectral lines and, thus, resolve the hyperfine levels of the excited state. We expect our results to make single-ion spectroscopy accessible to a larger scientific community.