Nonvolatile switchable dual-functional THz metamaterial with selective transmission and adjustable absorption...

Area of Science:

• Metamaterials
• Terahertz (THz) technology
• Photonics

Background:

• Integrating tunable characteristics and dual functions into single THz metamaterials is a key research area.
• Quasi-bound states in the continuum (q-BICs) offer a promising mechanism for advanced metamaterial functionalities.

Purpose of the Study:

• To present a nonvolatile switchable dual-functional THz metamaterial.
• To achieve selective transmission and adjustable absorption using q-BICs.

Main Methods:

• Utilizing periodically arranged silicon disks tetramer to create q-BICs.
• Introducing asymmetry by manipulating silicon disk radii to transition from symmetry-protected BICs (SP-BICs) to q-BICs.
• Employing Ge2Sb2Te5 (GST) as a phase-change material for switching functionalities.

Main Results:

• Achieved selective transmission (bandstop filter) when GST is in the amorphous state.
• Demonstrated adjustable absorption when GST transitions to the crystalline state via heating, utilizing q-BICs and Fabry-Pérot resonance (FPR).
• Explained the underlying physics using multipole decomposition and temporal coupled-mode theory (CMT).

Conclusions:

• The proposed THz metamaterial exhibits nonvolatile switchable dual functionality.
• The q-BIC mechanism, combined with phase-change materials, enables versatile THz applications.
• This research offers valuable insights for designing advanced switchable and dual-functional THz metamaterials.