Resonance Anomalies in the Lamellar Grating

Negative Role of Surface Plasmons in the Transmission of Metallic Gratings with Very Narrow Slits

“…As a consequence, it is appropriate to invoke surface currents, rather than SP, as the general mechanism responsible for the extraordinary transmission. Surface currents exist both on real and perfectly conducting metal surfaces and are well known to enhance the transmission through perfectly metallic subwavelength apertures [15]. Perhaps, the close energy proximity of Rayleigh anomalies and of SP resonance may have rendered confusing the interpretation in previous works.…”

A General Modal Theory for Reflection Gratings

“…A set of real-valued functions t/ P (x, y), which is similar to the set of eigenfunctions for the lamellar grating [7][8][9], is defined by the relation By linearity, 4P is a solution of the Helmholtz equation, and satisfies .the condition given by (7) . The functions 01 (x, y) form an orthogonal set on y = 0 for 0 < x < c .…”

“…method has only been rigorously applied to specific grating profiles . These are the rectangular (lamellar) profile [7][8][9], the triangular profile [10] and the semicircular profile [11] . In [9], a modal method for the relatively simple lamellar grating has been exploited extensively to explain the resonance behaviour of that grating in terms of complex poles in the mode amplitudes .…”

The multilayer modal method for electromagnetic scattering from surfaces with several arbitrarily shaped grooves

“…T h e investigations of diffraction from corrugated surfaces with finite length were not restricted to perfect conductors, but highly conducting and dielectric materials have also been considered [2,31. Even the case of surfaces having a single protuberance or cavity have been widely treated by several different methods [4-71. Modal methods have been widely used for scattering from periodic gratings with highly symmetric grooves, like rectangular [8], triangular [9], semicircular [lo] or wire gratings [ l l ] . For perfectly conducting infinite periodic gratings, Andrewartha et al developed a modal theory that is suitable for arbitrary shapes of the grooves, but it presents numerical instabilities for deep cavities [12].…”