High-sensitivity optical Faraday magnetometry with intracavity electromagnetically induced transparency

We suggest a multiatom cavity quantum electrodynamics system for the detection of a weak magnetic field, based on Faraday rotation with intracavity electromagnetically induced transparency. Our study demonstrates that the collective coupling between the cavity modes and the atomic ensemble can be used to improve the sensitivity. With single-probe photon input, the sensitivity is inversely proportional to the number of atoms, and a sensitivity of 2.45 nT Hz–1/2 could be attained. With multiphoton measurement, our numerical calculations show that the magnetic field sensitivity can be improved to 105.6 aT Hz–1/2 with realistic experimental conditions.