High-quality trapped modes in all-dielectric metamaterials

Area of Science:

• Photonics and Metamaterials
• Dielectric Resonators
• Optical Physics

Background:

• All-dielectric metamaterials offer unique optical properties due to resonant dielectric structures.
• Subwavelength dielectric particles with engineered geometries can support various electromagnetic modes.
• Understanding mode formation is crucial for designing advanced optical devices.

Purpose of the Study:

• To investigate resonant states in a planar all-dielectric metamaterial composed of dielectric disks with penetrating holes.
• To establish a correlation between particle geometric asymmetry and the excitation of Mie-type and trapped modes.
• To evaluate the efficacy of different hole geometries for exciting trapped modes.

Main Methods:

• Theoretical analysis of a double-periodic lattice of subwavelength dielectric disks with off-centered holes.
• Identification of resonant states by analyzing transmitted spectra.
• Comparison of trapped mode excitation using round holes versus coaxial-sector notches.

Main Results:

• Resonant states were identified in the transmitted spectra, linked to individual resonator modes.
• A direct correlation was found between the asymmetry introduced by an off-centered hole and the formation of Mie-type and trapped modes.
• Coaxial-sector notches were shown to be advantageous for exciting trapped modes compared to round holes.

Conclusions:

• Geometric asymmetry in dielectric resonator particles plays a critical role in controlling resonant modes.
• Engineered holes, particularly coaxial-sector notches, offer enhanced control over trapped mode excitation in metamaterials.
• This research provides insights for designing novel all-dielectric metamaterials with tailored optical responses.