Developing a vector EIT magnetometer

We experimentally study a novel technique of detecting the magnitude and orientation of DC magnetic fields using electromagnetically induced transparency (EIT) resonances. Magnetic fields modify the separation between EIT spectrum peaks, independently of their orientation, allowing for magnetic field magnitude measurements. However, the resonance amplitudes depend on the field orientation relative to the light wave vector and polarization direction, making this system capable of vector measurements. Here we assess short-term stability and sensitivity of magnitude and field orientation measurements in ⁸⁷Rb hot atomic vapor, using phase-modulated linearly polarized coherent light.