A FRESNEL BI-PRISM DEVICE FOR ATOMIC MATTER WAVES

The principle of a simple bi-prism for coherent atomic translational w aves is studied. The scheme of the experiment consists of a diffractin g slit, in front of which the evanescent wave running along a tapered optical fibre provides a converging gradient of optical potential for two-level atoms. The combined effects of Fresnel diffraction and bi-pr ism interferences are described in different experimental configuratio ns. The influence of gravitation is outlined. Orders of magnitude and feasibility are discussed in the case of thermal neon atoms, for which experiments are under consideration. (C) 1997 Elsevier Science B.V.