Magnetometry based on nonlinear magneto-optical rotation with amplitude-modulated light

We report on an all-optical magnetometric technique based on nonlinear magneto-optical rotation with amplitude-modulated light. The method enables sensitive magnetic field measurements in a broad dynamic range. We demonstrate the sensitivity of 4.3×10−9G∕Hz at 10mG and the magnetic field tracking in a range of 40mG. The fundamental limits of the method sensitivity and factors determining current performance of the magnetometer are discussed.