Plasmonic mode coupling in three-dimensional metallic wire terahertz metamaterials

Area of Science:

• Condensed Matter Physics
• Metamaterials Science
• Terahertz (THz) Photonics

Background:

• Metallic wire structures are fundamental in metamaterials research.
• Understanding plasmonic mode coupling is crucial for designing advanced THz devices.
• Terahertz (THz) surface plasmon polaritons (SPPs) on metallic wires exhibit unique behaviors.

Purpose of the Study:

• To numerically investigate the plasmonic properties of 3D metallic wire-based THz metamaterials.
• To elucidate the mechanisms of plasmonic mode coupling in these structures.
• To explore potential applications in THz technologies.

Main Methods:

• Numerical simulations were employed to analyze two distinct structures: a bent wire array and a woven wire mesh.
• The study focused on the coupling of THz surface plasmon polariton (SPP) modes on individual metallic wires.
• Analysis included examining the transition to localized plasmonic modes and cross-guide coupling.

Main Results:

• Both bent wire arrays and woven wire meshes exhibit complex plasmonic behavior due to SPP mode coupling.
• The bent wire array demonstrates a bound state in the continuum and transitions to localized plasmonic modes with significant field enhancement (∼10^3).
• The woven wire mesh shows effective cross-guide directional coupling of SPPs between orthogonally oriented wires.

Conclusions:

• Metallic wire-based metamaterials offer versatile platforms for manipulating THz waves.
• Plasmonic mode coupling in these simple structures leads to sophisticated functionalities.
• The investigated structures show promise for THz plasmonic waveguiding, frequency filtering, and field enhancement applications.