Zero- and Low-Field Sensing with Nitrogen-Vacancy Centers

Over the years, an enormous effort has been made to establish nitrogen vacancy (N-$V$) centers in diamond as easily accessible and precise magnetic field sensors. However, most of their sensing protocols rely on application bias fields, preventing usage zero- or low-field experiments. We overcome this limitation by exploiting full spin $S=1$ nature N-$V$ center, allowing us detect nuclear signals at zero low with a linearly polarized microwave field. As conventional dynamical decoupling fail regime, we develop robust pulse sequences optimize pairs, which allow sense temperature weak ac fields achieve efficient from environmental noise. Our work allows for much broader simpler applications sensors regime can be further extended three-level systems ions atoms.