Scaling laws in velocity-selective coherent population trapping in the presence of polarization-gradient cooling

One-dimensional laser cooling based on velocity-selective coherent population trapping (VSCPT) on a 2(g)-->1(e) transition has been investigated numerically through the solution of the optical Bloch equations. As in the work of G. Morigi et al. [Phys. Rev. A 53, 2616 (1996)], it has been found that for a large set of atomic and laser parameters, the VSCPT cooling process may be described through scaling-law relations. The scaling laws are based on the relations between the loss rates at large atomic momentum and their dependence on the momentum around zero value. The role of the laser detuning on the VSCPT trapping efficiency has been examined and scaling laws including the detuning have been derived. [S1050-2947(97)01111-6].