Tunable Plasmon-Enhanced Wide-Angle Terahertz Perfect Absorption via Lorentz Media

Perfect absorption (PA) is central to spectroscopic sensing and integrated photonics. Existing mechanisms such as resonant metamaterials, multilayer interference cavities, and coherent or critical coupling schemes have achieved PA. Despite progress, realizing PA with simple structure and high integration at wide angles remains challenging. In this work, the dispersion is innovatively regulated by a composite matching mechanism of phase and amplitude, with a Lorentz-type dispersive dielectric providing the frequency-dependent phase response and controlled loss and a distributed Bragg reflector (DBR) supplying cavity feedback, together they realize wide-angle terahertz (THz) PA in a Tamm-type structure. Unlike traditional PA approaches that require thick dielectric layers and exhibit angular drift, this approach yields absorption above 92% for incidence angles up to $80°$ with a subwavelength top layer $\left(\sim \lambda /22\right)$ . By tuning the Lorentz parameters and the dielectric-layer thickness, we reconfigure the absorption spectrum without altering the remaining stack, enabling multichannel operation with less than 5.7% frequency shift under oblique incidence. The mechanism combines Lorentz-driven phase control with cavity feedback and provides a route to minimal patterning and tunable integration for on-chip photonics.