Numerical analysis of enhanced optical trapping force based on centripetal evanescent waves

A strong electric field enhancement was found at the center of an evanescent wave centripetally-propagated along the surface of a multilayer dielectric waveguide coating on a conical prism. Behaviors similar to the cylindrical vector polarization was observed and enhanced for three orders of magnitude in the same geometry by reconfiguring the incident angles. This enhanced electric field can be utilized to trap dielectric particles with a refractive index either higher or lower than the surroundings. The enhanced optical-trap, also versatile at various incident angles, was analyzed numerically with Rayleigh scattering approximation. Simulation results for optical trapping application are presented, showing a strong gradient force on the trapped particle yet keeping radiation force negligible.