Dual‐Band Angle‐Independent Terahertz Absorption via Coupled Modes in Hyperbolic‐Metamaterial‐Based Photonic Crystals Integrating Graphene and Gold Layers

The numerical design of a novel terahertz (THz) photonic heterostructure engineered for coupled mode, angle‐independent absorption spanning the 1–3 THz range is presented. The structure consists of a graphene monolayer sandwiched between two distinct one‐dimensional topological photonic crystals (TPC 1 and TPC 2 ), each incorporating hyperbolic metamaterials (HMMs) that induce topological interface states (TIS). The HMMs enable angle‐independent photonic bandgaps (PBGs) due to their anisotropic dispersion. The inclusion of a dielectric–gold bilayer adjacent to this structure, whose interface supports Tamm states, enables strong coupling between the TIS and Tamm modes, resulting in two pronounced absorption peaks within the PBG. The inclusion of HMMs significantly enhances anisotropic light confinement and intensifies hybridization between localized states, resulting in robust, broadband, and angle‐independent absorption. The findings highlight the heterostructure's capability to maintain spectral and amplitude stability of the absorption modes under varying incident angles, making it a promising platform for advanced THz photonic technologies.