Radiation control by defects in dark-state resonant photonic lattices

Area of Science:

• Optics and Photonics
• Metamaterials and Nanophotonics

Background:

• Resonant photonic lattices (PLs) typically exhibit bound states in the continuum (BIC) which are non-radiative.
• Symmetric PLs in a dark state generate only background scattering, lacking tunable radiation properties.

Purpose of the Study:

• To introduce and explain novel radiation properties in photonic lattices (PLs) engineered with defects.
• To demonstrate how defects can break lattice symmetry and excite leaky waveguide modes.

Main Methods:

• Analysis of a one-dimensional (1D) subwavelength membrane photonic lattice structure.
• Investigating the spectral and near-field profiles of defect-induced local resonant modes.

Main Results:

• Defects create local resonant modes, identified as asymmetric guided-mode resonances (aGMRs).
• These aGMRs lead to robust local resonance radiation, resulting in high reflection or high transmission at BIC wavelengths.
• Demonstrated defect-induced high reflection and high transmission in a lattice under normal incidence.

Conclusions:

• Defects in PLs are a viable mechanism for controlling radiation properties.
• The findings offer new pathways for radiation control in metamaterials and metasurfaces.