Design considerations of gold nanoantenna dimers for plasmomechanical transduction

Internal optical forces emerging from plasmonic interactions in gold nanodisc, nanocube and nanobar dimers were studied by the finite element method. A direct correlation between the electric-field enhancement and optical forces was found by observing the largest magnitude of optical forces in nanocube dimers. Moreover, further amplification of optical forces was achieved by employing optical power of the excitation source. The strength of optical forces was observed to be governed by the magnitude of polarisation density on the nanoparticles, which can be varied by modifying the nanoparticle geometry and source wavelength. This study allows us to recognise that nanoparticle geometry along with the inter-dimer distance are the most prominent design considerations for optimising optical forces in plasmonic dimers. The findings facilitate the realisation of all-optical modulation in a plasmomechanical nanopillar system, which has promising applications in ultra-sensitive nanomechanical sensing and building reconfigurable metamaterials. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

This study investigates the internal optical forces emerging from plasmonic interactions in gold nanodisc, nanocube, and nanobar dimers using the finite element method. The results demonstrate a direct correlation between electric-field enhancement and optical forces, with the largest magnitude observed in nanocube dimers. Furthermore, the optical forces can be further amplified by increasing the optical power of the excitation source. The strength of optical forces is found to be governed by the magnitude of polarization density on the nanoparticles, which can be adjusted by modifying the nanoparticle geometry and source wavelength. Overall, the findings highlight the significance of nanoparticle geometry and inter-dimer distance in optimizing optical forces in plasmonic dimers.