Manipulation of spin polarization of rubidium atoms by optical pumping with both

In this paper, we experimentally study the manipulation of the atomic spin polarization of rubidium atoms via optical pumping beams in resonance with both D1 and D2 transitions. In the presence of buffer and quenching gases, the D1 pumping beam with σ+ polarization creates atomic spin polarization along the direction of the beam, while the D2 pumping beam creates atomic spin polarization in the opposite direction. When the D1 and D2 pumping beams are simultaneously applied, the pumping processes caused by the two beams compete with each other since the D1 and D2 transitions share the same ground states. Here, we demonstrate that the resulting spin polarization of rubidium atoms is sensitive to the intensity and frequency of the D1 and D2 pumping beams. Furthermore, we show that the spin polarizations of two isotopes, 85Rb and 87Rb, can be independently manipulated with the combination of the D1 and D1 pumping beams. This provides a convenient method to create spin polarization of two isotopes of rubidium atoms in a selective manner, which may be useful in studying the spin dynamics of different isotopes in an atomic ensemble of natural abundance