Scattering And Binding Force Of Complex Medium Particle System By Vector Shaped Beam

Due to the extensive applications in various fields such as particle size analysis,atmospheric environment monitoring,microwave remote sensing,micro-imaging,biological diagnosis and so on,the interactions of electromagnetic(light)wave with aggregated small particles have attracted considerable attention and have been an important and hot international research topic.The research on the shaped beam almost focused on its generation,modulation,propagation and the scattering properties by single particles.The interactions of the shaped beam with two or more multi-layered spherical particles and chiral spherical particles are still relatively new topics in the world and deserve further study.Based on the classical electromagnetic theory,this thesis principally investigated the scattering properties and binding force(BF)effects exerted on the aggregations of isotropic dielectric spheres,the heterogeneous multi-layered spherical particles and the chiral dielectric spherical particles illuminated by the shaped Gaussian beam and the vector high-order Bessel beam in different polarization.The main contributions and results of the thesis are as follows:1.Based on the generalized Lorenz-Mie theory(GLMT)and the translation addition theorem,the angular distributions of scattering intensity of Gaussian beam by multiple isotropic spheres is given.The influence of the beam waist width,spherical spacing,number of spheres,incident angle and beam center position on the angular distributions of scattering intensity of spherical particles with different structure distributions is numerically analyzed in detail.The further theory analysis is carried out on the BF between the sherical system,using the momentum conservation theorem of EM field,the mathematical expressions of lateral BF and axial BF exerted on each sphere in isotropic bi-phere system is deduced.With the same influence of the incident wavelength,polarization angle and particle radius,comparisons of the effects of elliptic Gaussian beam and circular Gaussian beam on the BF between isotropic bi-sphere are analyzed numerically.2.Based on the method of vector potential and plane wave angular spectrum,the unified specific expressions of scalar high-order Bessel beam(HOBB)are derived.Using GLMT and coordinate rotation theory,the SVWFs expansion and convergence of expansion coefficient of arbitrary linear polarization HOBB are studied.Combining the translation addition theorem,the angular distributions of scattering intensity of scalar HOBB by multiple isotropic spheres with arbitrary structure distribution is given.The variation of the scattering intensity of isotropic spherical particles with half conical angle,center position,incident angle and the distance between spheres is numerically analyzed.Based on the momentum conservation theorem of EM field,the BF between two isotropic spheres is studied analytically,the influence of isotropic spheres and beam parameters on the BF is numerically analyzed.3.Using the method of angular spectrum expansion,the EM field expansion of non-uniform vector HOBBs are obtained,and the electrical intensity distribution characteristics of linear polarization,circular polarization,radial polarization,angular polarization and non-polarization vector HOBBs are analyzed.Based on the GLMT,the scattering characteristics of concentrated multi-layered spheres by arbitrary incident HOBB in different polarizations are studied.The effects of spherical layer number,distance between spheres,incident angle,half-cone angle and polarization states on scattering characteristics are numerically analyzed.Using the momentum conservation theorem of EM field,the BF of particles in the multi-layered spherical system illuminated by non-uniform vector HOBBs is numerically simulated and analyzed.4.The spherical vector wave functions expansion of non-uniform vector HOBBs are obtained by using the GLMT.On the basis of the translation addition theorem and momentum conservation theorem of EM field,the angular distribution of the scattering field and the BF of the chiral bi-sphere induced by non-uniform vector HOBB are studied.The scattering field distribution and the BF effect of different beam polarization modes,topological charges,half conical angle of the beam,chiral parameters and particle size of the chiral bi-sphere are analyzed numerically.