Independently tunable dual-band near-infrared absorber based on borophene and Tamm plasmons

We propose a dual-band near-infrared absorber based on the simultaneous excitation of borophene localized surface plasmons (LSPs) and Tamm plasmon polaritons (TPPs). By leveraging the ultrahigh intrinsic carrier density of borophene, this hybrid architecture effectively overcomes the mid-infrared spectral limitations of conventional two-dimensional materials, achieving near-perfect peak absorptances of 98.1% and 97.2%. Theoretical and numerical investigations reveal that the in-plane LSP mode and the longitudinally distributed TPP mode exhibit a highly decoupled nature. The LSP resonance can be actively and independently modulated via the borophene ribbon geometry and electron density, whereas the TPP mode is strictly governed by the underlying one-dimensional photonic crystal and incident angle. Combined with a robust polarization-selective response, this structurally simple yet highly tunable platform offers a versatile physical paradigm for designing next-generation active optical modulators and polarization-sensitive nanophotonic devices.