PHASE-SHIFTS OF ATOMIC DEBROGLIE WAVES AT AN EVANESCENT-WAVE MIRROR

A detailed theoretical investigation of the reflection of an atomic de Broglie wave at an evanescent wave mirror is presented. The classical and the semiclassical descriptions of the reflection process are revi ewed, and a full wave-mechanical approach based on the analytical solu tion of the corresponding Schrodinger equation is presented. The phase shift at reflection is calculated exactly and interpreted in terms of instantaneous reflection of the atom at an effective mirror. Besides the semiclassical regime of reflection describable by the WKB method, a pure quantum regime of reflection is identified in the limit where t he incident de Broglie wavelength is large compared to the evanescent wave decay length.