A Method For Robust Spin Relaxometry in the Presence of Imperfect State Preparation

ABSTRACT Spin relaxometry using optically addressable spin systems has developed as a valuable tool in medical and condensed matter systems, offering the advantage of operating without the need for external DC or RF fields. Among optically addressable spin systems, nitrogen‐vacancy (NV) centers have been applied to paramagnetic sensing using both single crystal diamond and nanodiamond materials. However, these methods often suffer from artifacts and systematic uncertainties, particularly due to imperfect spin state preparation, leading to artificially fast relaxation times. Current analysis techniques fail to adequately account for these issues, limiting the precision of parameter estimation. In this work, we introduce a minimal fitting procedure that enables more robust parameter estimation in the presence of imperfect spin polarization. Our model improves upon existing approaches by offering more accurate fits and providing a framework for efficiently parallelizing single‐spin dynamics studies.