Self-Oscillating Rubidium Magnetometer using Nonlinear Magneto-Optical Rotation
P Schwindt, Leo W. Hollberg, John E. Kitching
The detection of nonlinear magneto-optical rotation (NMOR) of polarized light through alkali atomic vapor is a highly sensitive technique for measuring magnetic fields. We demonstrate that when using frequency modulated light to excite the NMOR resonance, it is possible to cause the system to self oscillate. The NMOR signal is not a simple replication of the sine wave modulation of the light, but rather contains many higher harmonics of the modulation frequency, and we implement two ways of processing the signal to recover the fundamental modulation frequency in the feedback loop and induce self oscillation. Self oscillation greatly simplifies and reduces the power consumption of the electronics required to operate a magnetometer making the NMOR technique more attractive for commercialized magnetic sensors.