Imaging Strain and Electric Fields in NV Ensembles using Stark Shift Measurements

TL;DR

This paper demonstrates how Stark shift measurements of NV centers in diamond can be used to image and quantify internal strain and external electric fields, enhancing understanding of diamond's quantum properties.

Contribution

It introduces a method to measure and map strain and electric fields in diamond using Stark shift spectroscopy of NV centers, including at avoided crossings.

Findings

Stark shift is enhanced at minimized axial magnetic field.

Strain-induced Stark shifts allow calculation of internal strain.

Electric fields are mapped within the diamond volume.

Abstract

We report measurements of optically detected magnetic resonance spectra of ensembles of negatively charged nitrogen-vacancy (NV) centers in diamonds in the presence of strain and DC external electric fields. The Stark shift of the spectral lines is stronger when the axial magnetic field along the NV centers quantization axis is minimized. The shift is also enhanced at avoided crossings between the hyperfine levels at an axial field of 77 uT. Since the intrinsic strain in the diamond also induces a Stark shift, we are able to calculate the magnitude and direction of the strain within the crystal. We also use the Stark effect to map the electric field in the diamond volume between patterned electrodes.