Defect modes in one-dimensional anisotropic photonic crystal

We theoretically analyze the defect states in a single-defect photonic crystal composed of anisotropic dielectric materials. This structure can trap light of a given frequency range and filter only a certain frequency light. It is shown that the defect modes appear as peaks in the transmission spectrum. Their numbers, intensities, and frequency positions are extremely sensitive to the incidence angle and the orientation of the principal axes of layers constituting the superlattice and the layer defect. Our structure offers a great variety of possibilities for creating and controlling the number and transmitted intensities of defect modes. It can be a good candidate for realizing a selective electromagnetic filter.