High-Quality Plasmonic Modes with Bloch Surface Waves Modulated by Metal Stripes

In recent years, surface plasmons (SPs) have been intensively studied and found to be useful for sensing and waveguide applications. The subwavelength confinement of SP modes has spurred the exploration of diverse plasmonic structures. Nevertheless, the inherent ohmic losses associated with metals critically restrict the propagation distances of SPs, thereby limiting device applicability. In this study, we propose a plasmonic waveguide by integrating the periodic multilayer structures supporting Bloch surface waves with metallic thin stripes. The modal characteristics at the wavelength of 1550 nm are analyzed using the finite element method. The results indicate that this structure supports plasmon modes characterized by low propagation losses and reduced mode field areas. Specifically, the proposed waveguide achieves mode field areas on the order of 10⁻⁴λ², propagation distances over 100 μm as well as high-quality factors exceeding 3000. These findings provide a promising approach for the design and realization of highly integrated plasmonic devices.