The sensor head sits on a rotating stage with the cell positioned at the stages center. The sensor head can freely rotate in the xz and yz-planes. is the angle by which the probe beam moves away from the position where the probe beam is perpendicular to the static magnetic field in xz-plane. is the angle by which the pump beam moves away from the position where the pump beam is perpendicular to the static magnetic field in yz-plane. represents angle between the axis of rotation and the rotating field vector. Notably, WP stands for Wollaston prism, and Q-PD stands for quadrant photodiode.
