Cancellation of nonlinear Zeeman shifts with light shifts
  Nonlinear Zeeman (NLZ) shifts arising from magnetic-field mixing of the two hyperfine ground-states in alkali atoms lead to splitting of magnetic-resonance lines. This is a major source of sensitivity degradation and the so-called "heading errors" of alkali-vapor atomic magnetometers operating in the geophysical field range (B approx. 0.2-0.7 G). Here, it is shown theoretically and experimentally that NLZ shifts can be effectively canceled by light shifts caused by a laser field of appropriate intensity, polarization and frequency, a technique that can be readily applied in practical situations. 
K. Jensen, V. M. Acosta, J. M. Higbie, M. P. Ledbetter, S. M.   Rochester and D. Budker