Deep‐subwavelength light confinement and transport in hybrid dielectric‐loaded metal wedges

The goal of confining light at the deep‐subwavelength scale while retaining moderate attenuation has been pursued for years in the field of plasmonics. However, few feasible configurations at present are excellent at balancing the tradeoff between confinement and loss. This work proposes to overcome the above limitation by using hybrid wedge structures, which consist of triangular metal wedges loaded with nanometric low/high‐index dielectric claddings. Owing to the superior guiding properties of wedge plasmons in conjunction with high refractive index contrast near wedge tips, the modal sizes can be squeezed into significantly smaller spaces than those of their conventional wedge and planar hybrid counterparts, while simultaneously featuring propagation distances over tens of micrometers at telecommunication wavelengths. Studies on the evolution from a single metallic wedge to semiconductor–insulator–metal wedge(s) reveal strategies for continuous improvement of the optical performance. Discussions concerning practical issues including crosstalk and mode excitation have further elucidated their potential in building high‐performance nanophotonic components.