S-Polarized Light-Induced UV–Vis Plasmonics in Al–Ag Dimers: A Theoretical Perspective

Abstract

The interaction of light with metallic nanoparticle dimers has gained significant attention due to the enhanced local electric fields generated within the nanogap region. In this study, a detailed theoretical investigation of plasmonic homodimers and heterodimers composed of Al and Ag, covering the deep ultraviolet to visible spectral range, is undertaken. Simulations are carried out using COMSOL Multiphysics version 5.6 to examine the effects of dimer composition, gap width and particle size on far-field optical responses. The localized surface plasmon resonance (LSPR) behavior with the systematic variation of dimer radii and interparticle spacing to explore their influence on resonance characteristics is focused on in particular. The results reveal a redshift in LSPR peaks as particle size increases, while a reduction in gap width induces a blueshift. Furthermore, the LSPR wavelength of the Al-Ag heterodimer consistently falls between those of the respective homodimers. These findings demonstrate that the plasmonic response of such dimers can be effectively tuned by adjusting geometric and material parameters, offering potential for tailored nanophotonic applications.