Excitation of tunable hybrid modes and Rabi splitting in topological nanophotonic structures

In this manuscript, a planar dielectric topological photonic structure is proposed to realize strong light–matter interaction through coherent coupling between topological edge states (TES) and topological resonator states (TRS). The heterostructure comprises two one-dimensional photonic crystals (1D-PhCs) with distinct Zak phases and overlapping photonic bandgaps, enabling robust TES excitation at 1737 nm. Introduction of localized defects supports the formation of hybridized modes exhibiting Rabi splitting and Fano-like asymmetric spectral profiles. The interaction mechanism, modeled via a coupled-oscillator framework, demonstrates the excitation of odd and even hybrid modes with tunable Rabi splitting energy. The impact of coupling strength, incidence angle, and surrounding medium on the excited hybrid mode wavelength and Rabi splitting energy is theoretically investigated. The proposed structure offers a promising platform for tunable filtering, nonlinear optics, and refractive index sensing by providing dynamic control over coupling strength and excited mode frequencies.