Nearly total nonspecular reflection with a large telescopic factor

Diffraction of TM- and TE-polarized plane waves by periodic structures with piecewise-regular regions, in which the incident and scattered wave fields are coupled, were numerically analyzed. Results show that nearly total nonspecular high-alpha reflection can occur by this type of grating. Nonspecular reflection occurs because modes are excited at close to the natural frequencies of the gratings, where the latter may be regarded as open electrodynamic structures. This type of grating and the analysis can be used in open resonators, microwave duplexers, fiber-optic multiplexers, and other devices which combine a high-frequency resolution with efficient energy conversion, and nearly 90-deg angular separation of the incident and reflected light beams.