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To address the challenge of extending terahertz absorbers toward the low-frequency end without sacrificing broadband efficiency or polarization/angle insensitivity, we introduce a hybridized-resonance architecture that couples in-plane resonances, longitudinal Fabry-Pérot (FP) cavity modes, and inter-cell air-gap waveguide modes.This coupling pushes the lower band edge to 0.20 THz while preserving high absorptance and incident-angle robustness, a capability valuable for applications spanning 0.1-2 THz. By exploiting controlled modal coupling, the structure promotes broadband impedance matching and controlled dissipation, thereby mitigating sensitivity to polarization and incidence. Full-wave simulations predict an average absorptance of 95% across 0.20-2.54 THz, a peak absorptance ≈ 100%, and a fractional bandwidth of ≈ 328% (normalized to the geometric center frequency), corresponding to a bandwidth ratio of 12.7:1 (i.e., 1270%). High absorptance is retained for linear polarization angles from 0° to 90° and for incidence angles up to 30°, making the device attractive for terahertz sensing and electromagnetic countermeasure applications and providing a practical blueprint for future absorber designs.
Niu et al. (Sun,) studied this question.