Light Pressure on a Chiral Spherical Particle in an Evanescent Field: Analytical Solution

Abstract

Analytical expressions are derived for calculating the light pressure force acting on a chiral spherical particle of arbitrary size relative to the wavelength in an evanescent field generated by total internal reflection of an electromagnetic wave incident at a planar interface between two dielectric media, while neglecting reflection of the particle-scattered field from the interface. The expressions are used to analyze the Cartesian components of the light pressure force as functions of particle size and the angle of incidence at the interface between right- and left-handed circularly polarized waves interacting with chiral spheres composed of dielectric materials and a negative-index metamaterials. In the context of the solved problem, it is demonstrated that the force of light pressure may differ significantly for incident waves of opposite circular polarizations, especially under force resonance conditions, which can be used to sort chiral particles in corresponding evanescent fields.