The features of three-dimensional photonic crystals with the space-depended dielectric

The features of three-dimensional (3D) photonic crystals (PCs) composed of air and space-depended dielectric constituent are theoretically investigated by the plane wave expansion method, and the formulas to compute dispersion curves are derived. The arrangement for the present PCs is that the space-depended dielectric spheres are surrounded by the air, and the embedded dielectric spheres are arranged according to the simple-cubic lattices. The relative permittivity of dielectric spheres is depend on the control parameters and space coordinates. The relationships between the parameters of proposed PCs and the band structures also are studied. The computed results demonstrate that the achieved photonic band gaps (PBGs) can be adjusted by those parameters as mentioned above. Compared to the conventional dielectric-air PCs with the same topology, the wider bandwidth of PBG can be observed in such PCs. The computed results also shows us another alternative away to realize the reconfigurable applications with the 3D PCs.