DOPPLER-TUNED MULTIPHOTON RESONANCES IN AN ATOM REFLECTION BY A STANDING EVANESCENT-WAVE

We analyze the condition of observation of Doppler-tuned multiphotonic (''doppleron'') resonances in an atom reflection by a standing evanes cent wave. A theoretical model based on Ehrenfest's theorem for extern al atomic motion is proposed. The light forces exerted by the stationa ry evanescent wave are calculated either with a perturbation approach, or with a continuous-fraction method. The appearance of the multiphot onic lines in the specularly reflected atomic beam is clearly shown. T hese predictions are in good agreement with previous and present exper imental results, which are discussed.