Electron spin contrast of Purcell-enhanced nitrogen-vacancy ensembles in nanodiamonds

TL;DR

This paper presents a new optical measurement method for nitrogen-vacancy (NV) ensembles in nanodiamonds, revealing that optimizing the far-field radiation pattern enhances spin readout sensitivity more effectively than increasing emission rates.

Contribution

The study introduces a novel optical measurement technique for NV ensemble spin contrast and highlights the importance of radiation pattern modification over emission rate enhancement.

Findings

Modifying the far field radiation pattern improves spin readout sensitivity.

The new method provides insights into the relationship between spin contrast and fluorescence lifetime.

Optimizing radiation pattern is more effective than emission rate enhancement for sensing.

Abstract

Nitrogen-vacancy centers in diamond allow for coherent spin state manipulation at room temperature, which could bring dramatic advances to nanoscale sensing and quantum information technology. We introduce a novel method for the optical measurement of the spin contrast in dense nitrogen-vacancy (NV) ensembles. This method brings a new insight into the interplay between the spin contrast and fluorescence lifetime. We show that for improving the spin readout sensitivity in NV ensembles, one should aim at modifying the far field radiation pattern rather than enhancing the emission rate.