| Popis: |
A modal expansion formulation is presented to rigorously describe the diffraction from a perfectly conducting reflection grating in which each element consists of a rectangular cavity beneath a smaller rectangular aperture. For both S and P polarized incident radiation the structure is shown to exhibit spectacular resonance behaviour, similar to the interference phenomena obtained with a Fabry-Perot interferometer. A single-mode truncation of the theory is used to explain the action and show that for a Littrow mounting in the -1 order, 100% efficiency is achieved at resonance. The cavity depth and width determine the resonant wavelengths, while the narrow aperture width is found to be sensitively related to the positions and half-widths of the maxima. |
