Harnessing Short-Range Surface Plasmons in Planar Silver Films via Disorder-Engineered Metasurfaces

Abstract: Short-range surface plasmon polaritons (SR-SPPs) can arise due to the hybridization of surface plasmon polaritons propagating along the two interfaces of a thin metal slab. In optics, they have gained particular interest for imaging and sensing applications, because of their short wavelengths at optical frequencies along with strong field enhancement. However, mediating the interaction of SR-SPPs with photons in planar films is difficult because of the large momentum mismatch. For efficient coupling, nanostructuring such thin films (~20nm thickness), or placing metallic nanostructures in close proximity to the planar film is technologically challenging and can strongly influence the SR-SPP properties. In this paper, harnessing SR-SPPs in planar silver films is demonstrated using disorder-engineered metasurfaces. The disorder-engineering is realized by the light-controlled growth of silver nanoparticles. The dispersion of the hybrid modes with the silver thickness is measured and compared with simulations. We anticipate these results to introduce a novel and facile method for harnessing SR-SPPs in planar optical systems and make use of their promising properties for imaging, sensing and nonlinear optics.