An optical magnetometer system and method for operation thereof are described. The optical magnetometer system comprises: at least one light source emitting one or more illumination beams and scanning frequency of illumination beams over a selected range; at least one vapor cell having alkali atoms positioned within path of the illumination beam; a detection unit position to collect beam passing though the vapor cell; at least one thermal unit positioned to vary temperature of the vapor cell; and a controller configured and operable for obtaining detection data from the detection unit and for operating said at least one thermal unit in a feedback loop, and wherein said feedback loop being directed at maintaining a relation between optical intensity measured at one of more measurement points associated with selected frequencies and detuning level at the one or more measurement points from Larmor frequency of the optical magnetometer system.