Spectral Broadening and Ultrafast Dynamics of a Nitrogen-Vacancy Center Ensemble in Diamond

TL;DR

This study uses multi-dimensional coherent spectroscopy to investigate the spectral properties and ultrafast dynamics of NV centers in diamond, revealing mechanisms like thermal dephasing and spectral diffusion that impact their stability.

Contribution

It provides detailed insights into the environmental interactions affecting NV centers, highlighting the intrinsic linewidth and temperature-dependent Stark effects for quantum sensing applications.

Findings

Thermal dephasing caused by vibrational modes

Ultrafast spectral diffusion on picosecond timescale

Intrinsic homogeneous linewidth in the tens of GHz range

Abstract

Many applications of nitrogen-vacancy (NV) centers in diamond crucially rely on a spectrally narrow and stable optical zero-phonon line transition. Though many impressive proof-of-principle experiments have been demonstrated, much work remains in engineering NV centers with spectral properties that are sufficiently robust for practical implementation. To elucidate the mechanisms underlying their interactions with the environment, we apply multi-dimensional coherent spectroscopy to an NV center ensemble in bulk diamond at cryogenic temperatures. Our spectra reveal thermal dephasing due to quasi-localized vibrational modes as well as ultrafast spectral diffusion on the picosecond timescale. The intrinsic, ensemble-averaged homogeneous linewidth is found to be in the tens of GHz range by extrapolating to zero temperature. We also observe a temperature-dependent Stark splitting of the excited state manifold, relevant to NV sensing protocols.