Plane-wave diffraction at a grating composed of left-handed materials

Binary gratings made of left-handed materials may be considered as novel tools for optical signal processing. In this work, their diffraction properties have been investigated with the help of a semi-analytical numerical method. The method uses an equivalent transmission-line formulation of Maxwell´s equations for periodic structures. Being fully vectorial, the formulation can accommodate for negative permittivity and permeability. Using it, one can exploit the circuit theory of transmission lines to develop an absolutely convergent computational method of analysis for periodic structures composed of left-handed materials. In such structures, complex modes have been observed.