Generations of dark hollow beams and their applications in laser cooling of atoms and all optical-type Bose－Einstein condensation

Abstract

We report on a new experimental result to generate dark hollow beams by using a geometric optical method.We propose two new methods to produce focused and localized hollow laser beams by using π-phates,Using Monte-Carlo simulations,we have studied the Sisyphus cooling of alkali atoms in pyramidal hollow beam gravito-optical traps,We discuss some potential applications of the dark hollow beams in atom optics and the preparation of an all optically-cooled and optically-trapped atomic Bose-Einstein condensation(BEC),Our research shows that an ultracold atomic sample with a temperature of -2uK can be obtained in the pyramidal hollw beam dipole trap and an all optical-type BEC may be realized in a far blue-detuned,hollw beam trap.