Study On Optical Binding Force Between Two Spheres By Shaped Gaussian Beam

The interaction between the particles and the shaped beams is one of the hot research topics in many theoretical investigations and engineering applications. The electric-magnetic scattering of the beam, the optical trapping and manipulating of the particles by the beam are the unquestionable focus of the research. It has an important significance and application prospects in the further research of the fields of electromagnetics and biomedical that the studies on the interaction between two or more spherical particles.This article refers to the study on the scattering characteristics and optical binding force of Gaussian beam with the bi-sphere system. The main results achieves in the thesis are summarized as follows:1、Based on spherical vector wave functions(SVWFs) and their coordinate rotation theory, the expressions of the fields in terms of the SWVFs and beam shape coefficients of a circular/elliptical Gaussian beam with an arbitrary propagating direction is derived. According to the Generalized Multiple Mie theory(GMM), the analytical expressions of the transverse and axial binding force exerted on each sphere of the bi-sphere system by an arbitrary incident shaped Gaussian beam are given. The effects of radius of the sphere, beam waist width and incident angle on the force exerted on each sphere are numerical calculated and analyzed.2、The scattering characteristics of chiral bi-sphere are firstly investigated. According to the SVWFs, the incident fields, scattering fields and internal fields of a chiral sphere are given. The interactive scattering coefficients and total scattering coefficients are derived by using the addition theorem of SVWFs. The angular distributions of total scattering intensity of chiral bi-sphere system are calculated. The effects of beam waist width, radius of spheres and chiral parameter for a Gaussian beam incident on two chiral spheres are numerically analyzed.3、According to the scattering of chiral bi-sphere system by a Gaussian beam and the research method of binding force between two isotropic spheres, the binding force between two chiral spheres illuminated by a Gaussian beam are researched by using GLMT-MST(Generalized Lorenz Mie theory and Maxwell Stress Tensor). Not only the precisely analytical expressions of the transverse and axial binding force are derived, but also the numerical results of binding force of each sphere are given. The effects of radius of spheres、chiral parameter on the binding force are analyzed.