DYNAMICS AND LIMITS OF LASER COOLING BY VELOCITY-SELECTIVE COHERENT POPULATION TRAPPING

A theoretical analysis of the one-dimensional cooling of atoms by velo city-selective coherent population trapping (VSCPT) is presented. The analysis is performed in the framework of both full quantum and quasi- classical (for the translational motion of atoms) approaches. The temp oral evolution of atomic momentum distribution and the efficiency of t he cooling method are considered. The analytical solution for an atomi c density matrix is obtained in the limit of large interaction time an d small kinetic momentum of the atom. It is the rate of the coherence relaxation between two low-lying states in the three-level A-configura tion; (2) due to this relaxation, the evolution of the atomic momentum distribution is divided into two stages: first, high narrow peaks cor responding to cold atoms are formed, second, they are slowly diffused.