Optical Forces Between Coupled Plasmonic Nano-particles near Metal Surfaces and Negative Index Material Waveguides

摘要

We present a study of light-induced forces between two coupled plasmonicnano-particles above various slab geometries including a metallic half-spaceand a 280-nm thick negative index material (NIM) slab waveguide. We investigateoptical forces by non-perturbatively calculating the scattered electric fieldvia a Green function technique which includes the particle interactions to allorders. For excitation frequencies near the surface plasmon polariton andslow-light waveguide modes of the metal and NIM, respectively, we find richlight-induced forces and significant dynamical back-action effects. Opticalquenching is found to be important in both metal and NIM planar geometries,which reduces the spatial range of the achievable inter-particle forces.However, reducing the loss in the NIM allows radiation to propagate through theslow-light modes more efficiently, thus causing the light-induced forces to bemore pronounced between the two particles. To highlight the underlyingmechanisms by which the particles couple, we connect our Green functioncalculations to various familiar quantities in quantum optics.