Red-shift effect on the zero-field splitting for negatively charged nitrogen-vacancy centres in diamond

Abstract The zero field splitting (ZFS) quantifies the energy difference for the ground electron spin-triplet of a negatively charged nitrogen-vacancy centre 3 3 The term of negatively charged nitrogen-vacancy centre is abbreviate as NV centre in this paper. in the absence of external fields in a diamond sample. ZFS is a key parameter for using NV centres as quantum sensors for probes of magnetic and electric fields, temperatures and strains. The ZFS is generally detected using coherent spin manipulation by sweeping microwaves (MWs) at frequencies close to resonance with the ZFS. In this article, we report our experimental observations of the red-shift effect on the ZFS as a function of the MW power for two different thermal environments of the sample. We find asymptotic properties of the red shifts of the ZFS. Given the identical initial thermal equilibrium states of the sample, the differences in the raw values of the ZFS between the two cases randomly vary from 47 kHz to 1505 kHz over the entire experimental range. According to the asymptotic approximation, the difference is reduced to 29 kHz–166 kHz with a standard deviation of 49 kHz, suggesting a significant elimination of the red-shift effect. To the best of our knowledge, no other study has addressed the quantification and elimination of the red shift-effect of the MW field dependence using the asymptotic approximation.