Optical force modulated by the charge transfer plasmons.

This article investigates the modulation of trapping potential and optical trapping force in a graphene charge transfer plasmon (CTP) structure composed of two graphene disks connected by a graphene charge transfer bridge. The structure supports two resonance modes: the screened bonding dipolar plasmon (sBDP) mode and the charge transfer plasmon (CTP) mode, both of which generate strong and dynamically tunable trapping potentials and forces for nanoparticles. By adjusting the Fermi energy and geometry (length and width) of the charge transfer bridge, the position and magnitude of electromagnetic hotspots—and thus nanoparticle trapping sites—can be controlled, enabling stable trapping and transport of nanoparticles as demonstrated through simulations of restricted Brownian motion. These findings suggest that the dual resonance modes of the graphene CTP structure offer promising avenues for advanced optical manipulation and particle sorting at the nanoscale.