Parametric study of optical forces acting upon nanoparticles in a single, or a standing, evanescent wave

We compare four different methods for calculating the optical forces acting upon nanoparticles illuminated either by a single evanescent wave or by an interference field of two counter-propagating coherent evanescent waves (standing evanescent wave). Two of the employed methods consider the effect of multiple reflections of the scattered field from the water-prism interface that generates the illuminating evanescent wave(s). Subsequently, we present a parametric study of the optical forces acting upon nanoparticles for different polarizations and propagation constants of the illuminating evanescent wave, particle sizes and refractive indices.