  Controlling the near field optical binding force can be a key factor for
particle clustering, aggregation and localized surface plasmon sensors. So far
there is no generic way to reverse the near field optical binding force for
plasmonic or dielectric nano-dimers of distinct shapes (cube, cylinder, ring,
sphere). In this article, for both plasmonic and dielectric objects, we have
demonstrated a general way to control the reversal of near field binding force
for different shaped dimer sets. The force reversal is achieved by simple
breaking of symmetry, considering the nano particles are half or less than half
immersed in an inhomogeneous dielectric background, i.e. at air-water
interface. Such reversals have been explained based on Fano resonance,
interference fields, unusual behavior of optical Lorentz force and image charge
theory. However, if the dimer set is placed over a dielectric interface or
fully inside a homogeneous medium, the sign of binding force does not reverse.
Our proposed configuration provides a generic mechanism of archiving binding
force reversal for both plasmonic and dielectric objects, which can be verified
by very simple experimental set-up.
