Experimental Evaluation of Chip-scale Atomic Magnetometer Sensitivity

We evaluate the performance of spin-exchange relaxation free magnetometry in a $1 mm$ thick microfabricated vapor cell experimentally and compare it with theoretical predictions at the $5 \frac{fT}{\sqrt{Hz}}$ sensitivity level. The magnetometer is operated by monitoring the polarization rotation of a linearly-polarized probe beam that traverses the cell perpendicular to a circularly-polarized pump beam. Specifically, we investigate the contribution of frequency and amplitude noise of the pump laser to the magnetometer noise.