Anisotropic dual-band mid infrared absorber using graphene–black phosphorene nanocrescents

We propose and numerically investigate an anisotropic dual-band infrared absorber based on a hybrid graphene–black phosphorus nanocrescent architecture. The designed metastructure exhibits two spectrally distinct and polarization-dependent absorption peaks with efficiencies exceeding 85%, arising from strong plasmon–polariton hybridization and anisotropic charge carrier dynamics. Graphene contributes tunable surface plasmon resonances through electrostatic gating, while black phosphorus provides in-plane anisotropy and broadband light–matter interaction. Finite-element method (FEM) simulations reveal that the absorption response can be actively modulated by adjusting the graphene Fermi level and the geometric parameters of the nanocrescent, enabling dynamic control over the resonance wavelengths. The proposed absorber operates in the mid-infrared range, making it highly promising for applications in molecular sensing, photodetection, and tunable optoelectronic devices. Our results highlight the potential of combining two-dimensional materials with engineered plasmonic nanostructures to realize multifunctional, reconfigurable, and polarization-sensitive infrared photonic devices.