Spectroscopy of resonantly saturated selective reflection from high-density rubidium vapor using the pump-probe technique.

We study the resonant saturation of selective reflection at the interface between a transparent dielectric and high-density rubidium vapor on the D 2 -line. Our estimates suggest that, within the selected atomic density range, the dipole–dipole self-broadening of the line can vary from 13.2 to 39.6 GHz. Two tunable lasers are used as sources of pump and probe beams with orthogonal linear polarizations. The selective reflection spectra of the probe laser beam are studied at different atomic densities and pump beam intensities ranging from 0 to 8.8 kW cm−2. At high pump intensities, narrow structures are observed around the pump beam frequency, which are associated with power broadening effects. Increasing the pump intensity reduces the spectral width and the magnitude of the selective reflection resonances. The intensity dependence of the width and the magnitude is measured. By adjusting the pump intensity, it is possible to control the spectral width and reflectivity. • Resonantly saturated selective reflection from high density Rb vapor is explored. • Probe and pump beams are orthogonally polarized which prevents coherent scattering. • Pump beam reduces magnitude and dipole broadening of reflection resonance. • Inside reflection resonance at high pump intensities, we observe narrow structure. • Nonlinear selective reflection could be used for development of fast modulator. [ABSTRACT FROM AUTHOR]