Twin defect modes in one-dimensional photonic crystals with a single-negative material defect

Twin defect modes are found in one-dimensional photonic crystals stacking with single-negative-permittivity and single-negative-permeability media layers and a single-negative defect. The frequency interval of the two defect modes can be changed by varying the thickness of the defect layer or the thickness ratio of the two stacking layers. Conditions for the emergence of such twin defect modes only relate to the phase thicknesses of the defect layer and the two stacking layers. In addition, the electric fields at the frequencies of the defect modes are strongly localized at the interfaces between the defect layer and its adjacent layers. (c) 2006 American Institute of Physics.