Study on the Properties of Switching Bandgap and Surface Plasmon Modes in 3-D Plasma Photonic Crystals With Pyrochlore Lattices in Core-Shell Structure

Abstract

The interesting properties of surface plasmon modes and switching bandgap of 3-D photonic crystals (PCs) with pyrochlore lattices that are composed of the core isotropic and positive-index dielectric spheres surrounded by the plasma shells inserted in the air, are theoretically investigated in detail on the basis of the plane wave expansion method. Numerical simulations show that the proposed core-shell structure can obtain the complete photonic bandgaps (PBGs) and a flatbands region. Compared with the conventional lattices, such as diamond, face-centered cubic, body-centered cubic, and simple cubic lattices, the larger PBG can be achieved in the pyrochlore arrangement. The flatbands region is determined by the existence of surface plasmon modes. If the thickness of plasma shell is larger than a threshold value, the dispersive curves of such 3-D PCs will be similar to those obtained from the same structure containing the pure plasma spheres. In this condition, the inserted core spheres also will not affect the band structures. It is also provided that the upper edge of flatbands region does not depend on the topology of PCs. Our results also demonstrate that the PBG can be manipulated appropriately by the radius of core dielectric sphere and the plasma frequency, respectively. Thus, the PBG can be obtained by replacing the pure plasma spheres with proposed core-shell structures to fabricate possibly and save the material in the realization.