  Nonlinear selective reflection from the interface YAG window-high density
rubidium vapor in the high-temperature cell is studied at the transition
5S$_{1/2}$-5P$_{3/2}$. In the experiment tunable pump and probe lasers are
used. The selective reflection spectra for the laser probe beam are
investigated at four different rubidium atomic densities and five different
pump beam intensities. The estimated dipole-dipole interaction-induced line
broadening varies from $13.2$ to $39.6$ GHz, the measured pumped intensities
change from $1.2$ to $8.8$ kW$\cdot$cm$^{-2}$. Growth of the pump intensity
causes reduction of the magnitude and the width of the recorded selective
reflection resonance. We suggest developing all-optical modulators on the basis
of nonlinear selective reflection.
