Resonant magneto-optic rotation for magnetometry using autonomous   frequency stabilization
  The operation of a high sensitive atomic magnetometer using resonant elliptically polarized light is demonstrated. The experimental geometry allows autonomous frequency stabilization of the laser, thereby offers compact operation of the overall device. The magnetometry is based on measurement of the zero magnetic field resonance in degenerate two level system using polarimetric detection and has a preliminary sensitivity of <10 pT/Hz1/2 @ 1 Hz. 
S. Pradhan, S. Mishra, R. Behera, Poornima, and K. Dasgupta
physics.atom-ph physics.optics