title: Differential theory of gratings made of anisotropic materials.
abstract: Arbitrary profiled gratings made with anisotropic materials are discussed; the anisotropic character concerns electric and/or magnetic properties. Our aim is to avoid the use of the staircase approximation of the profile, whose convergence is questionable. A coupled first-order differential-equation set is derived by taking into account Li's remarks about Fourier factorization [J. Opt. Soc. Am. A 13, 1870 (1996)], but the present formulation shows that, in return for a convenient form of the differential system, it is possible to use only the intuitive Laurent rule. Our method, when applied to the simpler case of isotropic gratings, is shown to be consistent with that of previous studies. Moreover, from the numerical point of view, the convergence of our formulation for an anisotropic grating is faster than that of the conventional differential method.
authors.affiliation: Department of Information and Communication Engineering, Faculty of Information Engineering, Fukuoka Institute of Technology, Japan. koki@fit.ac.jp
authors.forename: Koki
authors.initials: K
authors.lastname: Watanabe
authors.forename: Roger
authors.initials: R
authors.lastname: Petit
authors.forename: Michel
authors.initials: M
authors.lastname: Nevière