Transient behavior of optically excited vapor atoms near a solid interface as observed in evanescent wave emission

Abstract

Using a cw dye laser beam normally incident on a glass-Na-vapor interface, fluorescence excitation spectra of the ${D}_{1}$ line are measured. By observing the fluorescence transmitted into the glass above the angle of total reflection, only evanescent light emitted within about a wavelength distance from the interface is observed. The measured spectra show a cutoff on the high-frequency side which is direct evidence for the transient behavior of the induced polarization of resonantly excited vapor atoms which have collided at the solid interface.