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

摘要

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-phase plates. UsingMonte-Carlo simulations, we have studied the Sisyphus cooling of alkali atoms in pyramidal hollow beam gravito-opticaltraps. We discuss some potential applications of the dark hollow beams in atom optics and the preparation of an alloptically-cooled and optically-trapped atomic Bose-Einstein condensation (BEC).Our research shows that an ultracoldatomic sample with a temperature of ～ 2μK can be obtained in the pyramidal hollow beam dipole trap and an alloptical-type BEC may be realized in a far blue-detuned, hollow beam trap.