Pulsed optical saturation of selective reflection from high density atomic vapor in pump-probe experiment

We study the temporal behavior of saturated selective reflection from high-density rubidium vapor via the pulsed pump–probe technique. The variations in the reflectivity and switching time are measured at two atomic number densities, 1.2 · 10¹⁷ and 2.5 · 10¹⁷ cm⁻³, with various pump intensities. The experimental data demonstrate a steep reduction in the reflectivity at low pump intensities ( \(I_{\text{pump}}<3\) kW/cm²), and then, at high pump intensities ( \(I_{\text{pump}} > 3\) kW/cm²), the data dependence is converted to a practically flat function. In the high-intensity range, the switching time is reduced to ≈2 ns. It is possible to enhance the variation of the reflectivity, using the incidence angles for the probe beam close to the Brewster angle. Our experimental results can be applied to the development of an all-optical switch.