The Localized Enhancement of Surface Plasmon Standing Waves Interacting with Single Nanoparticles

Abstract

Real-time, high-sensitivity, and label-free detection to single nanoparticles has been achieved via visualizing the interaction between surface plasmon polaritons (SPPs) and nanoparticles, which is widely applied to chemistry and biology. In this work, aiming to enhance the detection sensitivity to nanoparticles, we explore the interaction of SPP standing waves with single nanoparticles. Compared with SPPs, the inhomogeneous fields of SPP standing waves modulate charge distributions around the particle and excite different electric dipole modes that tailor localized enhancements. For nanoparticles situating at electric antinodes of SPP standing waves, a vertical electric dipole is excited and highdensity charges are stimulated around nanoparticle-film nanocavities, leading to further increased localized enhancement. The localized enhancement experiences more increase with smaller particle size, lower dielectric constant of surrounding medium, and lower particle refractive index. Via tailoring the localized enhancement by SPP standing waves, the sensitivity of SPP microscopy can be improved, which would broaden its applications on nanotechnology, biomedicine, and environmental monitoring.

Exploring strong light-matter interaction: computational insights into hybrid states and propagation length of surface plasmon polaritons on metal-dielectric interfaces in the Kretschmann configuration

“…the direction. These two SPP waves interfere, gives an SPP standing wave pattern [19]. Illuminating two beams is a little tricky and has many challenges in experiments.…”