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

Abstract

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 highperformance intriguing nanophotonic components.

Mode confinement enhanced in hybrid Bloch surface wave long-range waveguide

“…A number of novel hybrid BSW waveguides have been proposed and reported recently 9 , 12 , 29 – 35 Taking full advantages of the strong mode confinement ability of SPP mode and the ultra-low loss light guiding of BSW mode, the best of both is combined by employing a metallic strip on top of a truncated periodic dielectric multilayer stack. This hybrid waveguide, which exploits the coupling between SPP and BSW modes, is demonstrated to achieve good mode confinement combined with long propagation length 30 , 31 .…”

Highly confined light guiding in a low-loss hybrid Bloch surface waveguide

“…Combining the truly deep-subwavelength mode confinement capability of SPP mode with the long-range propagation distance of BSP mode, several hybrid BSP waveguide configurations are demonstrated to be able to achieve tight field localization along with low propagation loss at telecommunication wavelength [7,8] . In addition, by exploiting BSP in photonic crystal/dielectric composites, such as dielectric nanowireloaded BSP waveguides and similar nano-ridge loaded guiding configuration, a class of hybrid BSP waveguide structures with special attention to enhance the mode confinement ability have been enabled and reported to significantly improve the optical performance over its conventional counterparts [9,10] . These findings have effectively circumvented the tradeoff between the propagation distance and mode area, leading to a new idea to alleviate the weak mode confinement ability of traditional BSP waveguides.…”