A numerical approach based on the boundary-element method (BEM) is described for the analysis of plane-wave diffraction from groove-type gratings. First, the diffraction problem is exactly analyzed as a two-medium boundary-value problem. Further, for metallic gratings, a simple method in which an approximate boundary condition using the surface impedance is combined with the BEM is proposed. Both cases of the TE- and TM-wave incidences are systematically formulated. Numerical examples are presented for dielectric holographic gratings and metallic Fourier gratings, and the validity of the BEM and the effectiveness of the surface-impedance approximation are confirmed.
© 1990 Optical Society of America
Original Manuscript: June 16, 1989
Manuscript Accepted: October 24, 1989
Published: August 1, 1990
Yasunori Nakata and Masanori Koshiba, "Boundary-element analysis of plane-wave diffraction from groove-type dielectric and metallic gratings," J. Opt. Soc. Am. A 7, 1494-1502 (1990)