Li’s Fourier factorization rules [J. Opt. Soc. Am. A 13, 1870 (1996)] should be applied to achieve a fast convergence rate in the analysis of diffraction gratings with the Fourier modal method. I show, however, that Li’s inverse rule cannot be applied for periodic patterns of graphene when the conventional boundary condition is used. I derive an approximate boundary condition in which a nonzero but sufficiently small height is assumed for the boundary. The proposed boundary condition enables us to apply the inverse rule, leading to a significantly improved convergence rate. A periodic array of graphene ribbons is in fact a special type of finite-conductivity strip grating, and thus the proposed approach is also applicable to these kinds of structures.
© 2013 Optical Society of America
Diffraction and Gratings
Original Manuscript: June 4, 2013
Revised Manuscript: July 9, 2013
Manuscript Accepted: July 9, 2013
Published: August 7, 2013
Amin Khavasi, "Fast convergent Fourier modal method for the analysis of periodic arrays of graphene ribbons," Opt. Lett. 38, 3009-3012 (2013)