Electromagnetically-induced transparency in a diamond spin ensemble enables all-optical electromagnetic field sensing

TL;DR

This paper demonstrates the use of electromagnetically-induced transparency in diamond NV centers for all-optical sensing of electric and magnetic fields with high sensitivity and potential applications in quantum technologies.

Contribution

It introduces a novel diamond-EIT setup that achieves narrow resonances and high contrast, enabling sensitive all-optical field measurements at cryogenic temperatures.

Findings

Achieved EIT resonances with >6% contrast and 0.4 MHz linewidth.

Projected photon-shot-noise-limited sensitivities of 0.2 V/cm/Hz^{1/2} and 0.1 nT/Hz^{1/2}.

Demonstrated a diamond-EIT magnetometer with sub-nT noise floor.

Abstract

We use electromagnetically-induced transparency (EIT) to probe the narrow electron-spin resonance of nitrogen-vacancy centers in diamond. Working with a multi-pass diamond chip at temperatures 6-30 K, the zero-phonon absorption line (637 nm) exhibits an optical depth of 6 and inhomogenous linewidth of ~30 GHz full-width-at-half-maximum (FWHM). Simultaneous optical excitation at two frequencies separated by the ground-state zero-field splitting (2.88 GHz), reveals EIT resonances with a contrast exceeding 6% and FWHM down to 0.4 MHz. The resonances provide an all-optical probe of external electric and magnetic fields with a projected photon-shot-noise-limited sensitivity of 0.2 V/cm/sqrt(Hz) and 0.1 nT/sqrt(Hz), respectively. Operation of a prototype diamond-EIT magnetometer measures a noise floor of less than 1 nT/sqrt(Hz) for frequencies above 10 Hz and Allan deviation of 1.3 +/- 1.1 nT for 100 s intervals. The results demonstrate the potential of diamond-EIT devices for applications ranging from quantum-optical memory to few-photon nonlinear optics, precision measurement, and tests of fundamental physics.