The focusing and collimation effects of cold atomic clouds passing through a far red-detuned focused Gaussian beam

This work has theoretically studied the optical properties, such as the object-image relation and the focal length of the atom-optical lens created by far red-detuned Gaussian laser beam perpendicular to the propagation direction of the atomic cloud. Furthermore we have thoroughly studied the collimation effect when the cold atomic clouds passing through the laser beam. The effective transverse temperature can reach tens nanokelvin, which is far smaller than that by 1D polarization gradient cooling.