On The Numerical Study Of Deep Lamellar Gratings In The Resonance Domain

In the resonance domain (i.e. when the grating spacing d and the wavelength λ are of the same order of magnitude), the efficiencies of gratings can be determined from Maxwell's equations using integral or differential methods provided that the groove deep h is not too large (h/d is less than 0.5 for most of the gratings used in spectroscopy). However, for both practical applications (Z.O.D. systems, color separation, selective absorbers) and theoretical purposes, there is a need for the study of very deep gratings (h/d >> 1). This is why a new method has been proposed by an australian research group for the theoretical study of deep and very deep lamellar (or even multistep lamellar) gratings. The australian authors (A.A.) reported that their method works as well for dielectric as for lossy dielectric or metallic gratings.