Tunable Surface Plasmon-Polaritons Interaction in All-Metal Pyramidal Metasurfaces: Unveiling Principles and Significance for Biosensing Applications

In this work, we demonstrated a tunable double anticrossing interaction resulting from the interplay between two LSPR modes and an SPP wave in an all-metal pyramidal metasurface. The tuning is done as a function of the variation of the angle of incidence of the input electric field. From the double anticrossing, it was demonstrated that at certain angles of incidence, the intensity field obtained at specific wavelengths is strongly favored due to the nature of the pyramidal structures used, which consequently would benefit applications such as SERS, as shown in this manuscript. The implemented geometry enables the observation of an LSPR mode, which controls and synchronizes other resonances while also providing high sensitivity to surface changes, demonstrating sensitivities 103 times higher than those achieved in conventional systems based on LSPR when detecting the P. brasiliensis antigen.