Double-resonance optical pumping of Rb atoms

We have studied double-resonance optical pumping (DROP) as a function of the polarization combination of lasers, laser power, and the alignment of lasers in the 5S1/2-5P3/2-D3/2,5/2 ladder-type system of 87Rb atoms. By considering the two-photon transition probability and optical pumping effects, the changes in the relative magnitude of the DROP hyperfine structures as a function of the polarization combination of the lasers were analyzed theoretically. The theoretical results are in good agreement with the experimental results. Owing to the low optical pumping effect in the cycling transition, we could see the dependence of the spectrum on the laser power in the 5P3/2-4D5/2 transition distinctly. Also, the spectral linewidths as a function of the alignment between the lasers were measured 12.2 MHz for copropagating beams and 6.9 MHz for counterpropagating beams