Towards a miniature atomic scalar magnetometer using a liquid crystal polarization rotator

Abstract This paper reviews the progress made in the miniaturization of an isotropic space-qualified optically pumped magnetometer. Sensor isotropy is provided by a liquid crystal polarization rotator that sets the linear pumping beam polarization at 90° with respect to the ambient magnetic field. It allows a continuous polarization rotation from 0 to more than 300° with response times compatible with mobile or space applications. This rotator is nonmagnetic and can be easily integrated close to the gas cell. The miniature helium-4 sensor reaches a sensitivity of 10 pT/√Hz in a bandwidth from DC to 100 Hz.