On the efficiency of laser pumping of hyperfine structure sublevels of Rubidium-87 and Cesium-133 atoms

Abstract

The evolution of the hyperfine structure magnetic sublevel populations of 87Rb and 133Cs atoms in resonant linearly polarized laser fields is theoretically analyzed. Analytical expressions are obtained for stationary populations of the magnetic sublevels of the ground state 52S1/2 Fg = 1, Ff = 2 in 87Rb and 62S1/2 Fg = 3, Ff = 4 in 133Cs under optical pumping at the Fg ↔ Fe = Fg and Ff ↔ Fe = Ff transitions of the D2 lines (n 2S1/2 n 2P3/2) versus the initial populations. The characteristic population stabilization time are obtained by numerical solution for the density matrix equations, depending on the intensity of the laser fields and the detuning of the optical resonance. It is shown that the alternation of the polarization direction of the laser field at the transition Ff ↔ Fe = Ff almost completely transfers atoms to the lower sublevel of the “clock” M1 transition Fg M = 0 ↔ Ff M = 0 in rubidium and cesium frequency standards, which proportionally increases the signal of the recording system.