Anisotropy-dependent circular polarization spectroscopy

We have experimentally investigated the anisotropy-dependent circular polarization spectra of the Cs 6sS1/2→6p P3/2→10s S1/2 double-resonance transition in the presence of Ar. Satisfaction of doubleresonance condition, achieved by use of a two-photon two-color pulse laser excitation scheme, was monitored by measurement of the intensity of the 9pP1/2→6s S1/2 cascade fluorescence at 361.73 nm. In the experiment anisotropies, namely, alignment and orientation in the 6pP3/2 level, were produced from circularly polarized light with positive helicity. Then, a circular polarization degree was measured when both lasers were circularly polarized with positive helicities, and alternately positive and negative helicities for the 6pP3/2→10s S1/2 transition. From the measurement, we obtained the orientation-dependent depolarization cross section in the 6pP3/2 level due to collisions with ground-level argon atoms. A disorientation cross section value of 151 42 Å2 is reported.