An integrated nitrogen-vacancy magnetometer with sub-nanotesla sensitivity for practical applications

The practical applications require the NV magnetometer to be transportable and highly sensitive. In this study, we have demonstrated a portable NV magnetometer consisting of a sensor head and miniaturized control system with a volume of 22cm×19cm×12cm, which can operate outside the laboratory when connected to a computer. The sensor exhibited a sensitivity of 892.7pT/Hz
^1/2
, achieved through the use of a fluorescence omni-directional reflection concentrator (FORC) and common mode laser noise rejection technology. Notably, the FORC increased the fluorescence collection efficiency to 57% by allowing the collection of fluorescence emitted from all six facets of the diamond. Our work is expected to facilitate the transition of NV magnetometers from a laboratory platform to practical applications.