Mesure de l'impulsion echangee au cours de l'interaction onde evanescente-atome

In vacuo, during an interaction between a moving atom and a surface wave of frequency v, the exchanged momentum is greater than hv/c. First we show, using a semi-classical treatment, that this momentum is ?k_x in agreement with De Broglie's relation p = ?k, but unlike the usual notion of wave momentum attached to the Poynting vector. We present experimental methods to measure this momentum and we give results for two atom speeds.