Abstract All-optical Atomic Magnetometry using Nonlinear Magneto-optical Effects

Improvements were made to the existing rubidium atomic magnetometer which uses nonlinear magneto-optical rotation. Magnetic properties of the system were studied and are discussed in detail, including shielding, mapping, degaussing, sweep rate, and off axis fields. Laser parameters were also optimized, including beam intensity and frequency detuning, to determine the optimal settings for this system. An apparatus was developed to quantify the relaxation time of vapour cells, and ultimately determined that cell quality is the most important parameter presently limiting magnetometer performance, with 100 times further improvement possible in the future. The narrowest resonance width observed on the D1, 85Rb F = 3 → F = 2,3 resonance was 130 µG with a light intensity of ∼38 µW. Bandwidth limitations on our non zero amplitude modulated nonlinear magneto-optical rotation system were diagnosed and systematically removed so that operation is possible at frequencies of 100 kHz corresponding to fields of 100 mG. The precision of the magnetometer is presently ∼25 nG for quasi-DC fields