Velocity Selection Technique for High-Resolution Spectroscopy

It is known [1-3], that the samples of atoms with a velocity spread much lower than the recoil velocity uR= ħk/M (k is the wave number of exciting light field, M is the mass of atom) can be obtained by use of velocity selection with stimulated Raman transitions. A theoretical analysis of the velocity selection method is presented in [2,3]. So, it was shown in [2] that the formation of such narrow velocity structures is performed not only by the counterpropagating, but also by co-propagating light waves. This fact allows to form the two-dimensional velocity distribution of the widths δvx,y « uR by the velocity selection technique using laser configuration as in Fig. 1b.