Theory of deceleration of an atomic beam by an inhomogeneous optical field

A theoretical investigation is made of the radial motion of atoms in a beam decelerated by an opposite optical beam. It is shown that when the transverse size ρ of the laser beam is much greater than a certain critical value ρ_cr, then the interaction causes chiefly diffusion broadening of the atomic beam. If the laser beam radius is less than or of the order of ρ_cr, then monotonic diffusion broadening of the atomic beam is accompanied by oscillations due to the focusing effect of the laser beam.