Optical Stern-Gerlach effect from the Zeeman-like ac Stark shift

The Stern-Gerlach effect on a paramagnetic atom was demonstrated by simply using a light field in place of magnetic field. Since a laser beam can be tightly focused with lenses, made into a standing wave, and used for optical pumping, the laser-induced Stern-Gerlach force provides a versatile tool in optically manipulating atomic motion in a spin-dependent way. As a byproduct, a method of producing a slow atomic beam from a magneto-optical trap with better control on its velocity and population distributions was developed.