Scattering Of Gaussian Beam Research Articles

Correction: Laguerre–Gaussian Beam Scattering by a Perfect Electromagnetic Conductor (PEMC) Sphere

Correction: Laguerre–Gaussian Beam Scattering by a Perfect Electromagnetic Conductor (PEMC) Sphere

Laguerre–Gaussian Beam Scattering by a Perfect Electromagnetic Conductor (PEMC) Sphere

Laguerre–Gaussian Beam Scattering by a Perfect Electromagnetic Conductor (PEMC) Sphere

Elliptical Gaussian Beam Scattering and Modeling of Finite Length Anisotropic Medium Cylinder

Elliptical Gaussian Beam Scattering and Modeling of Finite Length Anisotropic Medium Cylinder

Scattering of a Gaussian beam by an anisotropic-coated eccentric conducting circular cylinder

AbstractA solution to the problem of Gaussian beam scattering by a circular perfect electric conductor coated with eccentrically anisotropic media is presented. The incident Gaussian beam source is expanded as an approximate expression in the simple form with Taylor's series. The transmitted field in the anisotropically coated region is expressed as an infinite summation of Eigen plane waves with different polar angles. The unknown coefficients of the scattered fields are obtained with the aid of the boundary conditions. The addition theorem for cylindrical functions is applied to transfer from the local coordinates to the global ones. The infinite series can be truncated under the prerequisite of achieving the solution convergence. Only the case of transverse-electric polarization is discussed. The similar formulation of transverse-magnetic polarization can be obtained by adopting a similar method. Some numerical results are presented and discussed. The result is in agreement with that available as expected when the eccentric geometry comes to the concentric one.

Astigmatic Gaussian Beam Scattering by a PEC Wedge

We are concerned with the scattering of a 3-D time harmonic astigmatic Gaussian beam from a perfectly electric conducting wedge. The incident wave object serves as the wave propagator of the phase-space beam summation method, which is a general framework for analyzing propagation of scalar and electromagnetic fields from extended sources. We perform asymptotic analysis for the total field including fields in the transition regions identifying the corresponding wave phenomena such as reflected beams and diffraction beams.

基于一阶彩虹区域高斯光散射的液滴测量

基于一阶彩虹区域高斯光散射的液滴测量

Scattering of a Gaussian beam by an anisotropically coated circular cylinder

A solution to the problem of Gaussian beam scattering by an anisotropically coated circular cylinder is presented. The incident Gaussian beam source is expanded as an approximate expression in the simple form with a Tayor’s series. The transmitted field in the anisotropically coated region is expressed as a infinite summation of eigen plane waves with different polar angles. The unknown coefficients of the scattered fields are obtained with the aid of the boundary conditions. The infinite series can be truncated under the prerequisite of achieving the solution convergence. Only the case of transverse-electric polarization is discussed. The similar formulation of transverse-magnetic polarization can be obtained by adopting the similar method. Some numerical results are presented and discussed. The result is in agreement with that available as expected when the Gaussian beam degenerates to a plane wave incidence case.

Scattering of a Gaussian beam on a deterministic medium under the first-order Born approximation

Abstract The scattering of a Gaussian beam on a deterministic medium within the accuracy of the first-order Born approximation is investigated by using its angular spectrum representation. The analytical expression for the far-field spectral density of the scattered field is derived. The numerical results show that the normalized spectral density of the scattered field is closely related with the effective radius of the scattering potential and the beam width of the incident Gaussian beam.

Scattering of on-axis Gaussian beam by a uniaxial anisotropic object.

Based on the extended boundary condition method, a semi-analytical solution to the scattering of an on-axis Gaussian beam by an arbitrarily shaped uniaxial anisotropic object is constructed. For the on-axis incident Gaussian beam, scattered fields as well as internal fields are expanded in terms of appropriate spherical vector wave functions, and the unknown expansion coefficients of the scattered fields are determined by using Schelkunoff's equivalence theorem and continuous boundary conditions. Numerical results of the normalized differential scattering cross section are presented, and the scattering characteristics are discussed concisely.

Scattering of on-axis Gaussian beam by an arbitrarily shaped chiral object

Based on a combination of the extended boundary condition method (EBCM) and generalized Lorenz-Mie theory (GLMT), a semi-analytical solution to the scattering of an on-axis Gaussian beam by an arbitrarily shaped chiral object is constructed, by expanding the incident Gaussian beam, scattered fields as well as internal fields in terms of appropriate spherical vector wave functions (SVWFs). The unknown expansion coefficients are determined by using Schelkunoff׳s equivalence theorem and continuous boundary conditions. Numerical results of the normalized differential scattering cross-section are presented, and the scattering characteristics are discussed concisely.

Scattering of a Gaussian beam by an elliptical cylinder using the vectorial complex ray model

The scattered waves of a shaped beam by an infinite cylinder in the far field are, stricto sensu, neither cylindrical nor spherical, so the asymptotic form of special functions involved in the theories based on the rigorous solution of Maxwell equations cannot be used to evaluate scattered intensities, even in the most simple case of Gaussian beam scattering by an infinite circular cylinder. Thus, although theories exist for the scattering of a shaped beam by infinite cylinders with circular and elliptical sections, the numerical calculations are limited to the near field. The vectorial complex ray model (VCRM) developed by Ren et al. describes waves by rays with a new property: the curvature of the wavefront. It is suitable to deal with the scattering of an arbitrarily shaped beam by a particle with a smooth surface of any form. In this paper, we apply this method to the scattering of an infinite elliptical cylinder illuminated by a Gaussian beam at normal incidence with an arbitrary position and orientation relative to the symmetric axis of the elliptical section of the cylinder. The method for calculating the curvature of an arbitrary surface is given and applied in the determination of the two curvature radii of the Gaussian beam wavefront at any point. Scattered intensities for different parameters of the beam and the particle as well as observation distance are presented to reveal the scattering properties and new phenomena observed in the beam scattering by an infinite elliptical cylinder.

Scattering of on-axis Gaussian beam by a chiral spheroid

Within the generalized Lorenz-Mie theory framework, an analytic solution to the scattering of an on-axis Gaussian beam by a chiral spheroid is presented by expanding the incident Gaussian beam, scattered fields as well as internal fields in terms of appropriate spheroidal vector wave functions. The unknown expansion coefficients are determined by a system of linear equations derived from the boundary conditions. Numerical results of the normalized differential scattering cross section are shown, and the scattering characteristics are discussed concisely.

Stimulated Brillouin Scattering of Gaussian Laser Beam in Relativistic Plasma

This paper presents an investigation of stimulated Brillouin scattering (SBS) of Gaussian laser beam in relativistic plasma. The pump beam interacts with a pre-excited ion-acoustic wave thereby generating a back-scattered wave. In the high intensity laser beam, electron oscillatory velocity becomes comparable to the velocity of light, which modifies the refractive index of plasma due to increase in the electron mass. This modification of refractive index affects the incident laser beam, ion-acoustic wave and back scattered beam. We have set up non-linear differential equations for the beam width parameters of the main beam, ion-acoustic wave, back-scattered wave and derived expression of SBS-reflectivity by taking full non-linear part of the dielectric constant of relativistic plasma with the help of moment theory approach. It is observed from the analysis that focusing of waves greatly affects the SBS reflectivity.

Scattering of on-axis Gaussian beam by a conducting spheroid with confocal chiral coating

Within the generalized Lorenz–Mie theory framework, an analytical solution to the scattering by a chiral-coated conducting spheroid, for incidence of an on-axis Gaussian beam, is constructed by expanding the incident Gaussian beam, scattered fields as well as internal fields in terms of appropriate spheroidal vector wave functions. The unknown expansion coefficients are determined by a system of linear equations derived from the boundary conditions. Numerical results of the normalized differential scattering cross section are presented, and the scattering characteristics are discussed concisely.

Scattering of Gaussian beam by arbitrarily shaped inhomogeneous particles

A hybrid finite element-boundary integral method is applied to characterize the scattering of an arbitrarily incident-focused Gaussian beam by arbitrarily shaped inhomogeneous particles. Specifically, the Davis–Barton fifth-order approximation in combination with rotation Euler angles is used to represent the arbitrarily incident Gaussian beams. The finite element method is employed to formulate the fields in the interior region of the inhomogeneous particle, while the boundary integral equation is applied to represent the fields in the exterior region. The interior and exterior fields are coupled by means of the field continuity conditions. To reduce the computational burden, the frontal method and the multilevel fast multipole algorithm are adopted to solve the resultant matrix equation. Numerical results for differential scattering cross sections of several selected inhomogeneous particles are presented and can be served as further study on this subject.

Scattering of Gaussian beam by arbitrarily shaped particles with multiple internal inclusions

In this paper, we introduce an efficient numerical method based on surface integral equations to characterize the scattering of an arbitrarily incident Gaussian beam by arbitrarily shaped particles with multiple internal inclusions. The incident Gaussian beam is described by the Davis-Barton fifth-order approximation in combination with rotation Euler angles. For numerical purposes, the surfaces of the host particle and the inclusions are modeled using small triangular patches and the established surface integral equations are discretized with the method of moments. The resultant matrix equation is solved by using a parallel implementation of conjugate gradient method on distributed-memory architectures. Some numerical results are included to illustrate the validity and capability of the developed method. These results are also expected to provide useful insights into the scattering of Gaussian beam by composite particles.

Off-Axis Gaussian Beam Scattering by an Anisotropic Coated Sphere

An analytical solution to the scattering of an off-axis Gaussian beam incident on an anisotropic coated sphere is proposed. Based on the local approximation of the off-axis beam shape coefficients, the field of the incident Gaussian beam is expanded using first spherical vector wave functions. By introducing the Fourier transform, the electromagnetic fields in the anisotropic layer are expressed as the addition of the first and the second spherical vector wave functions. The expansion coefficients are analytically derived by applying the continuous tangential boundary conditions to each interface among the internal isotropic dielectric or conducting sphere, the anisotropic shell, and the free space. The influence of the beam widths, the beam waist center positioning, and the size parameters of the spherical structure on the field distributions are analyzed. The applications of this theoretical development in the fields of biomedicine, target shielding, and anti-radar coating are numerically discussed. The accuracy of the theory is verified by comparing the numerical results reduced to the special cases of a plane wave incidence and the case of a homogeneous anisotropic sphere with results from a CST simulation and references.

Scattering of a Gaussian Beam by a Conducting Spheroidal Particle With Non-Confocal Dielectric Coating

A semi-analytic solution to the Gaussian beam scattering by a conducting spheroidal particle with non-confocal dielectric coating is obtained within the framework of the generalized Lorenz-Mie theory (GLMT). By virtue of a transformation between spheroidal and spherical vector wave functions, a theoretical procedure is developed to deal with the non-confocal boundary conditions. Numerical results of the normalized differential scattering cross section are evaluated for coated spheroidal particles.

Arbitrary direction incident Gaussian beam scattering by multispheres

Based on spherical vector wave functions and their coordinate rotation theory, the field of a Gaussian beam in terms of the spherical vector wave functions in an arbitrary unparallel Cartesian coordinate system is expanded. The beam shape coefficient and its convergence property are discussed in detail. Scattering of an arbitrary direction Gaussian beam by multiple homogeneous isotropic spheres is investigated. The effects of beam waist width, sphere separation distance, sphere number, beam centre positioning, and incident angle for a Gaussian beam with two polarization modes incident on various shaped sphere clusters are numerically studied. Moreover, the scattering characteristics of two kinds of shaped red blood cells illuminated by an arbitrary direction incident Gaussian beam with two polarization modes are investigated. Our results are expected to provide useful insights into particle sizing and the measurement of the scattering characteristics of blood corpuscle particles with laser diagnostic techniques.

Scattering of Gaussian beam by a spheroidal particle with a spherical inclusion at the center

An analytic solution to electromagnetic scattering by a spheroidal particle having a spherical inclusion at the center, for oblique incidence of a Gaussian beam, is obtained within the framework of the generalized Lorenz–Mie theory (GLMT). By virtue of a transformation between the spheroidal and spherical vector wave functions, a theoretical procedure is developed to deal with the boundary conditions. Numerical results of the normalized differential scattering cross section are evaluated.