Two-dimensional confined topological modes in all dielectric guided mode resonance structure through surface features

Abstract

Guided mode resonance (GMR) structures offer simplicity and have spectral resonance capabilities such as narrowband resonance, high Q-factor, whereas topological surface features offer spatial light control. In this paper, we explore the integration of the GMR structures with topological photonics to achieve extreme two-dimensional (2D) spatial confinement of light. With this integration, we propose a novel design that leverages discontinuous surface features (crosscut) to excite Jackiw—Rebbi (JR) solution, which describes relationship between Dirac equation and topological insulators. Finite element modelling, considering various structural and material parameters, demonstrate a 40% improvement in light confinement compared to benchmark GMR structures, with a calculated full width half maximum (FWHM) of the confined optical mode measured to be approximately ~ 18 ± 3 nm. This FWHM value represent the spatial extent of the confined optical field, indicating the achieved field localization in the proposed structures. This significant enhancement showcases the potential of our approach for applications demanding ultra- precise spatial resolution. Furthermore, tolerance studies reveal good robustness to variations in the dimensions of the crosscut and angle of polarization, ensuring practical feasibility. The proposed structure exhibited good tolerance of up to ~  ± 10%. This work paves the way for highly confined 2D light manipulation within all- dielectric platforms, opening exciting avenues for nanophotonic devices and applications requiring light localization.