We study the sensitive detection of a weak static magnetic field via Faraday rotation induced by an ensemble of spins in a bimodal degenerate microwave cavity. We determine the limit of the resolution for the sensitivity of the magnetometry achieved using either single-photon or multiphoton inputs. For the case of a microwave cavity containing an ensemble of nitrogen-vacancy defects in diamond, we obtain a magnetometry sensitivity exceeding 5.2nT/Hz utilizing a single-photon probe field, while for a multiphoton input we achieve a subfemtotesla sensitivity using a coherent-probe microwave field with power of Pin=1nW.
|Number of pages||8|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 12 Oct 2015|