Abstract

IAbstract. Scattering theory is developed for plane diffraction gratings. The author's theory of Rayleigh-Bloch wave expansions is used to construct wave operators and a scattering operator for such gratings. For gratings that admit no surface waves, transient wave fields near the gratings are shown to behave for large times like free waves and corresponding asymptotic wave functions are calculated. These results are applied to analyze the echoes from gratings of signals due to localized sources. Finally, the echoes of sources remote from the grating are estimated and shown to be completely characterized by the S-matrix and the signal waveform. 0,.9 cessi es. I'., DD- TAB3I ~ L