Emulated nuclear spin gyroscope with $^{15}$NV centers in diamond

Abstract: Nuclear spins in solid-state platforms are promising for building rotation sensors due to their long coherence times. Among these platforms, nitrogen-vacancy centers have attracted considerable attention with ambient operating conditions. However, the current performance of NV gyroscopes remains limited by the degraded coherence when operating with large spin ensembles. Protecting the coherence of these systems requires a systematic study of the coherence decay mechanism. Here we present the use of nitrogen-15 nuclear spins of NV centers in building gyroscopes, benefiting from its simpler energy structure and vanishing nuclear quadrupole term compared with nitrogen-14 nuclear spins, though suffering from different challenges in coherence protection. We systematically reveal the coherence decay mechanism of the nuclear spin in different NV electronic spin manifolds and further develop a robust coherence protection protocol based on controlling the NV electronic spin only, achieving a 15-fold dephasing time improvement. With the developed coherence protection, we demonstrate an emulated gyroscope by measuring a designed rotation rate pattern, showing an order-of-magnitude sensitivity improvement.