Scattering from a strip grating placed on a multilayer dielectric sheet

A simple analysis of scattering from a strip grating, placed on a multilayer dielectric surface is presented. The obliquely incident, arbitrarily polarized plane wave is decomposed into fast and slow polarized modes, and a complete and accurate solution of the generalized Fourier coefficients of the diffracted E and H fields is derived. As an example, the power diffracted into the zero transmitted order was determined for the case of a He-Ne laser beam incident on a photomask chrome-on-glass grating, having a period of 2 mu m. To account for the nonuniform thickness of the glass slab, the calculated zero order transmitted power values were averaged to account for a 50-nm thickness variation around a nominal thickness of 1.5 mm for the glass slab. A plot of the measured and theoretical linewidths for the photomask grating is given. Excellent agreement was obtained.<>