A Hybrid Plasmonic System Integrating Plasmon-Induced Transparency and Perfect Absorbance

We present a hybrid plasmonic platform that integrates plasmon-induced transparency (PIT) and perfect absorbance (PA) to achieve multi-band, tunable, and highly efficient light-matter interactions in the mid-infrared (mid-IR) spectral region. The system employs a dolmen-shaped nanoantenna configuration engineered to support the hybridization of bright dipole and dark quadrupole resonances. By systematically tuning structural parameters such as antenna separation and dielectric spacer thickness, the platform enables precise control over spectral splitting and absorption strength, giving rise to multiple perfect absorption peaks. To demonstrate the platform's utility for molecular sensing, we modeled a protein bilayer characterized by vibrational signatures at the Amide I, II and III bands. Our results demonstrate that this PIT-PA integrated platform not only achieves near-unity absorbance across multiple spectral bands but also enables the label-free detection of distinct protein vibrational modes with high sensitivity. The platform holds strong potential for applications in biosensing, photodetection, and infrared energy harvesting, where multi-band operation and spectral precision are critical.