Few NV Center Nanodiamonds Enable High-Speed and High-Resolution Sensing of Paramagnetic Species

Nitrogen vacancy (NV) centers in diamonds are a highly promising quantum sensing platform for various applications, including biosensing of magnetically tagged biomolecules. In this work, we have studied the interaction of an ensemble of nanodiamonds (NDs), each containing few (< 5) NV centers, with paramagnetic nanoparticles, through numerical simulations and experiments. Change in the NV center properties is interrogated by performing T 1 relaxometry and optically detected magnetic resonance (ODMR) measurements.