Frequency response of resonance modes in heterostructures composed of single-negative materials

Multiple resonance transmission modes are generated in one-dimensional photonic heterostructure stacking with single-negative-permittivity and single-negative-permeability media layers. By varying the thickness ratio of the two kinds of stacking layers, the resonance modes are found to merge at the middle of the forbidden bandgap. Conditions for the merging of the resonance modes are obtained from the effective medium theory. The frequency, frequency interval, and number of the resonance modes can be tuned as desired by adjusting the period number or the layer thicknesses of the heterostructures. Furthermore, each resonance mode can be split into as many transmission peaks as required. Such resonance modes are insensitive to incident angle, which can be utilized to design omnidirectional and multichannel filters.