Long-Term Characterizations of an Absolute Magnetometer Based on EIT*

Accurate magnetometers, such as proton magnetometers and Mz atomic magnetometers, play an important role in fields like navigation without GPS, ordnance detection, geomagnetic surveying, and fundamental physics. Such sensors lack the capability to yield vector information without external coil systems and calibration. Here, we present the development of a vector magnetometer based on electromagnetically induced transparency in a three-level system. This EIT magnetometer can produce scalar and vector information of a magnetic field simultaneously. We have measured the stability of such a magnetometer and find that the photon-shot noise limit is better than 20 pT/√Hz. Common systematics that affect the long-term stability and accuracy of the EIT magnetometer, like light shifts and pressure shifts, will be discussed.