Asymmetric dual-band perfect absorber induced by hybrid modes of Tamm and localized surface plasmon polaritons

With the widespread application and increasing development of photonic devices, the issue of the conflict between single-frequency performance and the complexity of multi-frequency structures in conventional absorbers has become more prominent. We designed an asymmetric perfect absorber capable of absorbing incident electromagnetic waves at dual-band frequencies. The asymmetry in this absorber primarily stems from the unique characteristics and hybridized coupling modes of the optical Tamm state and localized surface plasmon polaritons. The designed absorber can efficiently absorb incident electromagnetic waves from opposite directions, simultaneously achieving both high-efficiency bidirectional absorption at shared frequency and hybrid-mode-enabled multiband absorption. It maintains relative absorption efficiencies exceeding 90% at different frequencies. Notably, it exhibits polarization independence and robustness to interfacial metal defects between the truncated photonic crystal and metallic films, a critical advantage for practical applications. The novel design of this asymmetric absorber based on hybrid modes is an instructive means of designing optical functional devices and offers potential applications in nanotechnology fields such as optical signal processing and imaging.