Ultra-high-Q substrate-mode coupled resonances in complementary THz metamaterial

Area of Science:

• Optics and Photonics
• Materials Science
• Metamaterials

Background:

• High-quality factor (Q) resonances in the terahertz (THz) range are crucial for advanced applications like sensors, filters, and emitters.
• Metamaterials offer a promising route to achieving these resonances, but metallic radiation losses in meta-atoms typically limit Q-factors.
• Existing THz metamaterial designs often struggle with significant energy dissipation, hindering their practical implementation.

Purpose of the Study:

• To investigate a novel complementary metallic disk-hole array (CMA) structure for enhanced THz resonances.
• To experimentally and numerically explore the coupling mechanisms responsible for high-Q resonances in the proposed CMA.
• To demonstrate a new approach for overcoming intrinsic metallic losses in THz metamaterials.

Main Methods:

• Fabrication and experimental characterization of the complementary metallic disk-hole array (CMA) structure.
• Numerical simulations to analyze the electromagnetic response and resonance behavior of the CMA.
• Investigation of the interplay between lattice resonances and Fabry-Pérot cavity resonances within the substrate.

Main Results:

• Experimentally achieved record-breaking Q-factors of up to 750 for the CMA structure at THz frequencies.
• Demonstrated in-substrate modes enabled by the unique CMA design, significantly enhancing resonance quality.
• Identified the synergistic coupling between lattice and cavity resonances as the key mechanism for high-Q performance.

Conclusions:

• The complementary metallic disk-hole array (CMA) presents a highly effective platform for achieving ultra-high Q-factors in THz metamaterials.
• This work establishes a new benchmark for Q-factors in free-space-coupled metallic metamaterial structures at THz frequencies.
• The findings pave the way for developing next-generation THz devices with unprecedented performance and efficiency.