The theory of light scattering from an interface covered by a periodic grating near the threshold of transformation of one of the diffraction beams from a traveling wave to an evanescent one is developed and compared with experiments. It is shown that the behavior of the scattered light near such thresholds provides rich information regarding both the medium in contact with the grating interface and the interface itself. © 1996 The American Physical Society.

• Received 15 January 1996

DOI:https://doi.org/10.1103/PhysRevE.54.912