Simulation of Gaussian electromagnetic wave interaction and its effect on the dynamics of metallic nanosphere (repulsion or even elasticity)

Abstract

In this paper, using the classical electromagnetic theory, the average force and the torque (moment of force) acting on a metallic nanosphere are investigated in the presence of a laser beam with Gaussian profile. The metallic nanosphere is modeled as a plasma nanosphere. It is found that the laser beam can apply both effective force and effective force torque to the nanosphere, being useful for the optical manipulation in the destruction of cancerous tissues, and the delivery of drugs to them. For this purpose, a mathematical model is presented for scattering phenomenon of the Gaussian laser beam from a metallic sphere. The spatial distribution of electric field inside the sphere is calculated, thus achieving the force density function inserted on each volume element of the sphere. Variations of the torque and the average force exerted on the metallic sphere are presented in terms of basic parameters such as the effective cross section of the laser beam, the relative distance between the front mirror of laser structure and sphere center, the operating frequency of the laser beam, nanosphere density and the radius of nanosphere.