Low-Loss Light Guiding at the Subwavelength Scale in a Nanowire-Loaded Hybrid Bloch-Surface-Polariton Waveguide

We report the realization of strongly confined low-loss optical waveguiding at telecommunication wavelength by exploiting the hybridization of photonic modes guided by coupled dielectric mode and Bloch surface polaritons on the interface between one-dimensional photonic crystal and dielectric nanowire. Owing to the combined effects induced by the coupling between two types of guided modes, tight field localization in conjunction with significantly lower propagation loss can be achieved simultaneously. The characteristics of the hybrid modes are comprehensively numerically investigated through tuning key structural parameters of the coupled dielectric nanowire and its distance to the photonic crystal surface. The hybrid mode could effectively balance the compromise between the mode confinement and propagation loss for a wide geometrical parameter range. It reveals the hybrid mode is capable of enabling larger propagation distance (centimeter level) with subwavelength mode confinement, leading to a high figure of merit nearly one order of magnitude larger as compared to the conventional hybrid waves in dielectric-metal-based surface plasmon waveguides over the range of dimensions considered. The outstanding properties of the proposed guiding scheme could open up possibilities for a variety of high-performance intriguing nanophotonic components.