Engineering optical gradient force from coupled surface plasmon polariton modes in nanoscale plasmonic waveguides
Lu Jiahui, Wang Guanghui†,
       

Optical gradient force of symmetric and antisymmetric SPP modes versus the relative permittivity εs of the gap dielectric for different metal filling ratios with gap width d = 60 nm. Panels (a) and (b) are for structure A, (c) and (d) for structure B.