The effect of surface interaction on the performance of submillimeter atomic magnetometers

We have studied the effect of surface interaction on the performance of submillimeter atomic magnetometers. We use an evanescent wave magnetometer with a coated cell of adjustable length. The cell length varies from a few millimeters to less than 100 $\mu m$. Two kinds of antirelaxation coatings are used: octadecyltrichlorosilane (OTS) and dichlorooctamethyltetrasiloxane (Surfasil). Sub-kHz linewidth can be achieved for a 100 micron thick OTS-coated cell. Magnetometers with coated ultra thin cells have superior performance in inhomogeneous magnetic fields, and can achieve a spatial resolution of better than 25~$\mu m$.