Precision measurement and spectroscopy with diamond NV centers

Precision measurements of the electron-spin precession of nitrogen-vacancy (NV) centers in diamond form the basis of numerous applications, ranging from imaging nanomagnetism to nuclear magnetic resonance (NMR) spectroscopy, gyroscopes, magnetometry, and searches for new spin physics. Solid-state spins offer advantages over alkali-vapor and SQUID sensors in that a high density of immobile spins form a tunable sensing voxel that can be tailored for a given application. However, the scaling up of NV sensors to large ensembles, as needed for the most sensitivity-demanding applications, has proved challenging. These experiments require the ability to measure changes in ~10 GHz electron-spin transitions at the sub-mHz level, i.e. a fractional resolution of better than 10^(-13). This is a regime that is only routinely realized in the field of atomic clocks. The ultimate limits in NV sensing precision are fundamental and cannot be avoided (e.g., spin projection noise), but some sources of noise are due to experimental imperfections and can be mitigated. I will discuss methods being developed to overcome challenges due to microwave phase noise and laser heating. I will present our latest progress towards implementing these methods in NV-detected NMR spectroscopy and femtotesla magnetometry [1].