We present an experimental module on electromagnetically induced transparency (EIT) in a Hanle configuration aimed to application for precise metrology. The EIT line width of the order of hundred hertz equivalent to nano-Tesla magnetic flux density has been achieved in rubidium atomic vapors with Ne buffer gases at room temperature. It can be interest for build of EIT based all-optical compact magnetometers, competitive to the most sensitive magnetometers based on superconducting quantum interference devices.
Magnetic sensors are widely used in many applications including medical diagnostics, geomagnetic survey, etc. Scalar atomic magnetometers that have demonstrated sensitivity at and below fT/ Hz^1/2 level can be adapted to include measurement of magnetic field orientation but usually at the cost of accuracy and with limitation of dynamic range. Magnetometry using electromagnetically induced transparency (EIT) instead was used to provide both scalar accuracy and vector information with angle resolution at a level of 10-3 deg/Hz^1/2. We present a scheme for EIT vector magnetic field measurement with the common-mode drift suppression by probing multiple EIT resonances. The demonstrated sensitivity is stable to < 200 pT/ Hz^1/2 at 1 mHz.
We develop a generalized principle of electromagnetically induced transparency (EIT) vector magnetometry based on high-contrast EIT resonances and the symmetry of atom-light interaction in the linearly polarized bichromatic fields. Operation of such vector magnetometer on the
D1 line of
87Rb has been demonstrated. The proposed compass-magnetometer has an increased immunity to shifts produced by quadratic Zeeman and ac-Stark effects, as well as by atom-buffer gas and atom-atom collisions. In our proof-of-principle experiment the detected angular sensitivity to magnetic field orientation is ${10}^{\ensuremath{-}3}$ deg/Hz
1/2, which is limited by laser intensity fluctuations, light polarization quality, and magnitude of the magnetic field.