Continuous microwave hole burning and population oscillations in a diamond spin ensemble

TL;DR

This study investigates continuous spectral hole burning and population oscillations in a diamond spin ensemble, revealing narrow homogeneous linewidths and hyperfine interactions, with implications for quantum sensing and information processing.

Contribution

It demonstrates the observation of narrow homogeneous spectral features and population oscillations in a diamond spin ensemble, including hyperfine interactions, using continuous spectral hole burning techniques.

Findings

Homogeneous hole linewidths are up to three orders narrower than inhomogeneous linewidths.

Population oscillations decay beyond 5 Hz detuning and are modeled with five-level rate equations.

Hyperfine interactions with $^{13}$C and $^7$Li are identified within the ensemble.

Abstract

Continuous spectral hole burning and spin-level population oscillations are studied in an inhomogeneously broadened diamond-based spin ensemble composed of substitutional nitrogen and nitrogen-vacancy centres created through neutron irradiation and annealing. The burnt spectral features highlight a detuning-dependent homogeneous hole linewidth that is up to three orders of magnitude narrower than the total inhomogeneous ensemble linewidth. Continuous population oscillations are observed to quickly decay beyond a pump and probe detuning of 5 Hz, and are numerically modelled using a five-level system of coupled rate equations. Fourier analysis of these oscillations highlight discrete $^{13}$C hyperfine interactions, with energies within the inhomogeneous ensemble linewidth, as well as suspected nuclear $3/2$-spin coupled signatures likely related to the $^7$Li byproduct of neutron irradiation.