Abstract
The development of artificial materials, termed photonic metamaterials, has led to phenomena that do not exist in natural materials. The properties of metamaterials are derived both from the properties of their constituent materials and the geometrical arrangement. The constituent materials are usually arranged in periodic patterns, manipulating the waves in the ways that are unachievable with conventional materials. Such periodic structures with chiral morphology are capable of inducing chiroptical effects with respect to righthanded circularly polarized (RCP) light and left-handed circularly polarized (LCP) light, leading to new types of circular polarization-sensitive devices. In addition, by studying dispersion characteristics, some interesting optical properties can be discovered. In this work, we present studies based on finite-difference time-domain (FDTD) method for analyzing the polarization-dependent properties and dispersion relation characteristics of dielectric helix and dielectric single gyroid (SG) structures. The corresponding band structures, circular dichroism (CD) indices, coupling indices and reflectance spectra are examined to verify circular polarization-dependent properties. The dispersion surfaces and equi-frequency contours (EFCs) are applied to discover interesting wave guiding characteristics including negative refraction. Moreover, we also investigate how the frequency ranges of these optical properties are tailored by varying the refractive index and structural parameters of the structures. These results are crucial for the design of functional devices at optical frequencies based on dielectric SG and helix structures.