Microwave-Free Vector Magnetometry with Nitrogen-Vacancy Centers along a Single Axis in Diamond

Sensing vector magnetic fields is important to many applications in fundamental physics, bioimaging, and materials science. Sensors exploiting nitrogen-vacancy (N-V) centers typically interrogate N-V ensembles oriented in all directions, thwarting nanoscale spatial resolution. Utilizing the level anticrossing in the triplet ground state, the authors demonstrate a $m{{0}{0ex}}i{{0}{0ex}}c{{0}{0ex}}r{{0}{0ex}}o{{0}{0ex}}w{{0}{0ex}}a{{0}{0ex}}v{{0}{0ex}}e{-}f{{0}{0ex}}r{{0}{0ex}}e{{0}{0ex}}e$ vector magnetometer that simultaneously measures all Cartesian components of the field, offering wide-band operation and high, equal sensitivity in all directions. This technique may work for single N-V centers as well as ensembles, extending vector measurements to the nanoscale, at ambient temperatures.