Study On Scattering Of Gaussian Beam By A Spherical Particle With An Eccentric Spherical Inclusion

Most of particles encountered in many industrial process and scientific research have eccentric structures caused by many effects for instance its character, mechanism of form, industrial process, practical need, etc. Such as Cell consisting of a nuclei, atmospheric aerosols, melting ice sphere, etc. The incident beam can be considered as plane wave when the scatters are very small compared to the dimension of the incident beam . But more generally, the beam shape must be considered when the size of the scatterer is relatively large and the illumination on the scatterer is not homogeneous. On the basis of scattering of plane wave by a spherical particle with an eccentric spherical inclusion, this thesis is devoted to the systemic research on scattering of Gaussian beam by a spherical particle with an eccentric spherical inclusion and its applications on many techniques. The main works and achievements are summarized as follows:1. In order to study the scattering of the Gaussian beam with an eccentrically stratified dielectric sphere easily, formula of vector spherical wave functions and the transform coefficients for corresponding additional theorem are given.2. Based on the generalized Lorenz-Mie theory(GLMT),the scattering characteristics of an eccentrically stratified dielectric sphere are studied. The translational addition theorems for spherical vector wave functions and the boundary conditions are used in solving the scattering coefficients. The eccentrically stratified dielectric sphere model is used to study the scattering characteristics of a nucleated biological cell illuminated by a Gaussian beam. Numerical results and the dependence of scattering characteristics on displacement distance, the beam waist radius and the size of the nucleus are discussed. Resonance of backscattered field for eccentric sphere illuminated by Gaussian beam is numerically simulated and analyzed.3. Based on the generalized Lorenz-Mie theory,using the formula of beam shape coefficients with arbitrary illumination, the scattering characteristics of Gaussian beam and a eccentric sphere is studied. The simulations are validated for plane wave scattering by an eccentric sphere and shaped beam scattering by a coated sphere. The far-field scattering and extinction efficiency factors of scattering of a Gaussian beam by an eccentric sphere in the general case of oblique illumination are discussed.4. Formula of radiation forces exerted on an eccentric sphere by a focused Gaussian beam is developed within the framework of the generalized Lorenz-Mie theory (GLMT). Numerical results of the radiation force for an eccentric sphere are given. By reducing the eccentric sphere to a concentric sphere system, the expression of axial force exerted on an eccentric sphere by a focused Gaussian beam is validated. The effects of distance between centers, beam waist, refractive-index and wavelength on axial radiation force are discussed. Resonance of longitudinal radiation force for eccentric sphere illuminated by Gaussian beam is numerically simulated and analyzed.