Guiding light through quasi-TE modes embedded in the radiation continuum

Area of Science:

• Photonics
• Waveguide Optics
• Condensed Matter Physics

Background:

• Bound states in the continuum (BICs) are localized states within the continuous spectrum of radiation.
• Existing BIC configurations often lack efficient guiding in low-refractive-index materials.

Purpose of the Study:

• To introduce a novel type of bound state in the continuum (BIC).
• To demonstrate guiding of quasi-transverse electric (TE) modes in a lower refractive index core within a coupled waveguide system.

Main Methods:

• Theoretical investigation of coupled photonic waveguide structures.
• Analysis of eigenmode spectra and continuum embedding.
• Parameter tuning to suppress coupling and induce BIC formation.

Main Results:

• A new BIC configuration is identified in coupled waveguides.
• The BIC emerges when coupling between waveguides is suppressed.
• Genuine guiding of quasi-TE modes is achieved in the lower refractive index core.

Conclusions:

• This work presents a novel BIC that overcomes limitations of previous designs.
• The demonstrated guiding capability in lower refractive index cores opens new avenues for photonic device applications.