Time-resolved UV-IR pump-stimulated emission pump spectroscopy to probe the collisional dynamics of highly excited cesium vapor

We have used a pump-stimulated emission pump spectroscopic technique to measure the collisional dynamics in the highly excited level of $^{133}Cs$ atomic vapor. Aligned $8p\,^2P_{3/2}$ cesium atoms were produced by a pump laser. A second laser, stimulated emission pump, promoted the population exclusively down to the $5d\,^2D_{5/2}$ level. The intensity of the $5d\,^2D_{5/2}\rightarrow 6s\,^2S_{1/2}$ cascade fluorescence at 852.12 nm was monitored. The linear polarization degree for the $6s\,^2S_{1/2}\rightarrow8p\,^2P_{3/2}\rightarrow5d\,^2S_{5/2}$ transition was measured in the presence of argon gas at various pressures. From the measurement, we obtained the collisional cross section (disalignment cross section) value in the $8p\,^2P_{3/2}$ level cesium.