Evanescent wave diffraction of multi-level atoms

Diffraction of multi-level atoms by an evanescent wave reflective diffraction grating is modeled by numerically solving the time-dependent Schrodinger equation. We are able to explain the diffraction observed in experiments with metastable neon. This is not possible using a two-level atom model. The multi-level model predicts sensitive dependence of diffraction on the laser polarization. For pure p-polarization of the lasers a dark state forms. Associated with this is high order diffraction.