Interparticle-Coupled Metasurface for Infrared Plasmonic Absorption

Plasmonic metasurfaces operating in the long-wavelength infrared region (LWIR) are primarily employed for bio-sensing and imaging applications. The key factor affecting the capability of LWIR metasurfaces is absorption efficiency, whereas significant advances have been made to attain higher absorption intensities, using metal-insulator-metal (MIM) stack structures, which require a complex nanofabrication process and repetition of the patterning process to develop each layer. This study experimentally demonstrates the integration of metasurfaces with plasmonic resonators. The metasurfaces and plasmonic resonators are developed through electron beam lithography (EBL) on the same plane of the Silicon substrate. The fabricated prototype has broad incident angle stability at a bandwidth of 2 mu m with near-perfect absorption at 8 mu m resonance wavelength when characterized through the Attenuated Total Reflectance - Fourier Transforms Infrared Spectroscopy (ATR-FTIR) setup. The metasurface device achieves tunable resonance behavior when the incident angles reach up to 70 degrees. The proposed integration of metasurface with plasmonic resonators are well-suited for enhanced biosensing applications with metasurface devices.

Automated summary

Plasmonic metasurfaces operating in LWIR region are widely used for bio-sensing and imaging applications. This study presents a novel approach of integrating metasurfaces with plasmonic resonators, which can achieve high absorption efficiency and tunable resonance behavior. The fabricated prototype shows broad incident angle stability and near-perfect absorption at the resonance wavelength of 8 μm. This integration opens up new possibilities for enhanced biosensing applications with metasurface devices.