Intensity-gradient cooling of atoms in a localized-hol low beam*

Abstract

In this paper, we propose a new scheme to cool and trap neutral ato ms by using a blue-detuned localized hollow beam (LHB), and studied the dynamica l process of intensity-gradient cooling of the trapped atoms in the LHB by means of Monte-Carlo simulations. Our study shows that an ultracold atomic sample wit h a temperature of ～5 μK and an atomic density of 1012—1013/cm 3 can be obtained in our single LHB, and this atomic density can be con trolled by changing the relative aperture of the lens system. So, such a LHB can be used to realize an all-optical atomic Bose-Einstein condensation.