Perfect Absorption Efficiency Circular Nanodisk Array Integrated with a Reactive Impedance Surface with High Field...

Area of Science:

• Photonics and Plasmonics
• Metamaterials
• Infrared Spectroscopy

Background:

• Metal-insulator-metal (MIM) absorbers offer high performance but struggle with low field enhancement when using ultrathin spacers.
• Enhancing electric field confinement is crucial for improving the sensitivity of plasmonic sensors and spectroscopic techniques.

Purpose of the Study:

• To propose and demonstrate a novel MIM absorber structure that overcomes the limitations of ultrathin spacers.
• To achieve significant electric field enhancement and near-perfect infrared absorption.
• To enhance the performance of localized surface plasmon resonance (LSPR) sensors and surface-enhanced infrared spectroscopy (SEIS).

Main Methods:

• Integration of a reactive impedance surface (RIS) into the MIM absorber architecture.
• Design and optimization of a circular nanodisk array on an RIS.
• Impedance matching with vacuum to achieve near-perfect absorption.
• Characterization of electric field enhancement and absorption spectra at terahertz frequencies.

Main Results:

• The proposed RIS-integrated MIM absorber achieved an electric field enhancement factor of 180.
• Near-perfect absorption of 98% was obtained at 230 THz.
• The absorber demonstrated robust performance across different polarizations of incident waves.

Conclusions:

• The RIS-integrated MIM absorber effectively boosts field enhancement without requiring ultrathin spacers.
• This novel design offers a promising platform for enhancing the sensitivity of LSPR sensors and SEIS applications.
• The structure provides a pathway for developing advanced infrared sensing and spectroscopy technologies.