Omnidirectional band gap in photonic hypercrystal

We conducted a theoretical investigation to explore the propagation of waves, transmission, and photonic band gap (PBG) in a ternary photonic hypercrystal (PHC). This PHC consists of alternating layers of three different materials: hyperbolic metamaterial, mu-negative material, and dielectric medium. The study employed two key methods: the effective medium theory and the transfer matrix method. These approaches enabled the analysis of transmission coefficient and dispersion relations, revealing the presence and tunability of PBGs. One significant finding was that a 1D binary PHC exhibits PBGs for TM polarization, whereas the ternary PHC achieves omnidirectional PBGs (OPBGs). This means that light is forbidden to propagate through the ternary PHC regardless of its polarization or incident angle. The ternary PHC design offers superior control over OPBGs, enabling the creation of highly efficient omnidirectional filters and reflectors. We investigated the properties and shifts of PBGs within the frequency spectrum where the material exhibits extreme dielectric anisotropy, characterized by vastly different permittivity values in different directions. Numerical findings reveal that band characteristics are highly sensitive to incident angle, layer thickness and period number. This dependence provides a powerful tuning mechanism for photonic devices. By adjusting these parameters, researchers can control the PBGs and tailor the device’s properties for specific application. Additionally, the study found that changing the number of periods in the PHC alters the number of transmission peaks. This allows for further control over the device’s behavior. Overall, the present study demonstrates that PHCs offer a versatile means of manipulating light propagation across a broad frequency range with minimal losses, offering numerous potential applications in nanophotonics.