Optical deformation of homogeneous and core-shell spherical particles

Abstract

We study the optical stress and deformation of a dielectric sphere by an arbitrary shaped electromagnetic beam. The incident optical beam is described within the framework of generalized Lorenz-Mie theory (GLMT). A model based on the stress balance across a static fluid interface is used to determine the optical deformation of a particle composed of concentric spherical shells. An important analytic expression for the optical deformation is derived. With this result, we examine the optical stress and deformation of (i) a homogeneous spherical particle and (ii) a sphere with a concentric spherical shell. Illumination by both linearly and circularly polarized Gaussian and zeroth-order Bessel beams are considered. Cases relevant to optical trapping and manipulation experiments are analyzed.