A detailed numerical investigation of anomalies in lossy metallic lamellar gratings is presented in a large interval of a wavelength-to-period λ/d ratio. A substantial increase in absorption (a decrease in the total diffracted energy) is observed. If λ/d is small enough (within the homogenized limit), the absorption can reach almost 100%. When the groove width is large enough, the anomalies are connected with mode resonances inside the grooves.
© 1994 Optical Society of America
Original Manuscript: July 15, 1992
Revised Manuscript: August 9, 1993
Published: August 1, 1994
E. Popov, L. Tsonev, and D. Maystre, "Lamellar metallic grating anomalies," Appl. Opt. 33, 5214-5219 (1994)