Van der Waals-induced spectral distortions in selective-reflection spectroscopy of Cs vapor: the strong atom-surface interaction regime.

Frequency-modulated selective-reflection spectroscopy of the 6S-7P Cs resonance line yields Doppler-free anomalous line shapes that we demonstrate to be fully dominated by the long-range atom-surface interaction potential. The spatial inhomogeneous broadening of the observed line shapes, as well as its dependence on the pressure, the nature of the dielectric window, and the light incidence angle, is fully interpreted with a z(-3) van der Waals attraction model. These experiments clearly prove the feasibility of a spectral analysis of atom-surface interactions.