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Ari Sihvola - One of the best experts on this subject based on the ideXlab platform.
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Can a Dielectric Sphere emulate the behavior of a surface impedance Sphereƒ
2019 URSI International Symposium on Electromagnetic Theory (EMTS), 2019Co-Authors: Dimitrios C. Tzarouchis, Pasi Ylä-oijala, Henrik Wallén, Ari SihvolaAbstract:We theoretically investigate whether a Dielectric Sphere can mimic the behavior of an equivalent surface impedance Sphere and we discuss some of the of emergent properties, such as cloaking (minimum scattering) and maximum absorption conditions.
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light scattering by a Dielectric Sphere perspectives on the mie resonances
Applied Sciences, 2018Co-Authors: Dimitrios C. Tzarouchis, Ari SihvolaAbstract:Light scattering by a small spherical particle, a central topic for electromagnetic scattering theory, is here considered. In this short review, some of the basic features of its resonant scattering behavior are covered. First, a general physical picture is described by a full electrodynamic perspective, the Lorenz–Mie theory. The resonant spectrum of a Dielectric Sphere reveals the existence of two distinctive types of polarization enhancement: the plasmonic and the Dielectric resonances. The corresponding electrostatic (Rayleigh) picture is analyzed and the polarizability of a homogeneous spherical inclusion is extracted. This description facilitates the identification of the first type of resonance, i.e., the localized surface plasmon (plasmonic) resonance, as a function of the permittivity. Moreover, the electrostatic picture is linked with the plasmon hybridization model through the case of a step-inhomogeneous structure, i.e., a core–shell Sphere. The connections between the electrostatic and electrodynamic models are reviewed in the small size limit and details on size-induced aspects, such as the dynamic depolarization and the radiation reaction on a small Sphere are exposed through the newly introduced Mie–Pade approximative perspective. The applicability of this approximation is further expanded including the second type of resonances, i.e., the Dielectric resonances. For this type of resonances, the Mie–Pade approximation reveals the main character of the two different cases of resonances of either magnetic or electric origin. A unified picture is therefore described encompassing both plasmonic and Dielectric resonances, and the resonant conditions of all three different types are extracted as functions of the permittivity and the size of the Sphere. Lastly, the directional scattering behavior of the first two Dielectric resonances is exposed in a simple manner, namely the Kerker conditions for maximum forward and backscattering between the first magnetic and electric dipole contributions of a Dielectric Sphere. The presented results address several prominent functional features, aiming at readers with either theoretical or applied interest for the scattering aspects of a resonant Sphere.
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resonant scattering characteristics of homogeneous Dielectric Sphere
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Dimitrios C. Tzarouchis, Pasi Ylaoijala, Ari SihvolaAbstract:In this paper, the classical problem of electromagnetic scattering by a single homogeneous Sphere is revisited. Main focus is the study of the scattering behavior as a function of the material contrast and the size parameters for all electric and magnetic resonances of a Dielectric Sphere. Specifically, the Pade approximants are introduced and utilized as an alternative system expansion of the Mie coefficients. Low order Pade approximants can give compact and physically insightful expressions for the scattering system and the enabled dynamic mechanisms. Higher order approximants are used for predicting accurately the resonant pole spectrum. These results are summarized into general pole formulae, covering up to fifth order magnetic and forth order electric resonances of a small Dielectric Sphere. Additionally, the connection between the radiative damping process and the resonant linewidth is investigated. The results obtained reveal the fundamental connection of the radiative damping mechanism with the maximum width occurring for each resonance. Finally, the suggested system ansatz is used for studying the resonant absorption maximum through a circuit-inspired perspective.
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Resonant Scattering Characteristics of Homogeneous Dielectric Sphere
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Dimitrios C. Tzarouchis, Pasi Ylä-oijala, Ari SihvolaAbstract:In the present article the classical problem of electromagnetic scattering by a single homogeneous Sphere is revisited. Main focus is the study of the scattering behavior as a function of the material contrast and the size parameters for all electric and magnetic resonances of a Dielectric Sphere. Specifically, the Pade approximants are introduced and utilized as an alternative system expansion of the Mie coefficients. Low order Pade approximants can give compact and physically insightful expressions for the scattering system and the enabled dynamic mechanisms. Higher order approximants are used for predicting accurately the resonant pole spectrum. These results are summarized into general pole formulae, covering up to fifth order magnetic and forth order electric resonances of a small Dielectric Sphere. Additionally, the connection between the radiative damping process and the resonant linewidth is investigated. The results obtained reveal the fundamental connection of the radiative damping mechanism with the maximum width occurring for each resonance. Finally, the suggested system ansatz is used for studying the resonant absorption maximum through a circuit-inspired perspective.
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Electrostatic image theory for layered Dielectric Sphere
IEE Proceedings H Microwaves Antennas and Propagation, 1992Co-Authors: I V Lindell, M.e. Ermutlu, Ari SihvolaAbstract:Static image theory for a homogeneous Dielectric Sphere, recently formulated by one of the authors, is generalised to the problem of a multilayer Dielectric Sphere in terms of a line-image charge. The imageline source is seen in this case to be in relation to the so-called static reflection coefficient that could be labelled as a finite Mellin transformation. This transformation is discussed and a Table of corresponding transforming functions is given. The result can be applied in a more complete quasistatic analysis of interactions of layered Dielectric spherical particles in an artificial Dielectric media. More closely, a two-layer Sphere is considered with special cases of a thin layer, and that of a low contrast between the layers. Numerical results are calculated for the radiowave propagation problem of attenuation due to melting hail particles, assumed to be composed of a spherical ice core with a spherical water shell.
Mohsen Yazdani - One of the best experts on this subject based on the ideXlab platform.
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transient electromagnetic scattering by a radially uniaxial Dielectric Sphere the generalized debye and mie series solutions
IEEE Transactions on Antennas and Propagation, 2016Co-Authors: Mohsen Yazdani, Joseph R. Mautz, Jay Kyoon Lee, E ArvasAbstract:In this paper, a theoretical study is carried out to determine the scattering of a transient electromagnetics wave by a radially uniaxial Dielectric Sphere. This is achieved by inverse Laplace transformation of the frequency-domain scattering solution. To improve understanding of the scattering mechanism from a uniaxial Dielectric Sphere, two different frequency-domain solutions are employed. In the first approach, the impulse and step responses of a uniaxial Dielectric Sphere are evaluated by the Mie series solution. Following the high-frequency (HF) scattering solution of a large uniaxial Sphere, the Mie series summation is split into high-frequency (HF) and low-frequency terms where the HF term is replaced by its asymptotic expression allowing a significant reduction in computation time of the numerical Bromwich integral. In the second approach, the generalized Debye series solution is introduced, and the generalized Mie series coefficients are replaced by their equivalent Debye series formulations. The results are then applied to evaluate the transient response of each individual Debye term allowing the identification of impulse returns in the transient response of a uniaxial Sphere. The effect of variation in permittivity on the arrival time as well as amplitudes of each impulse return is studied, and the results are compared with those computed using the Mie series solution. The numerical results obtained from both methods are in complete agreement.
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High-Frequency Scattering From Radially Uniaxial Dielectric Sphere
IEEE Antennas and Wireless Propagation Letters, 2015Co-Authors: Mohsen Yazdani, Joseph R. Mautz, Luke Murphy, Ercument ArvasAbstract:High-frequency backscattering caused by a large uniaxial Dielectric Sphere is presented in this letter. The term high frequency implies ${Ka} \gg 1$ where $K$ and $a$ are the propagation constant and radius of the Sphere, respectively. Using a modified Watson transformation, the slowly convergent generalized Mie series summation for a uniaxial Dielectric Sphere is transformed into a rapidly convergent contour integral. The generalized Debye series of the uniaxial Dielectric Spheres is introduced, and the Mie series coefficients are replaced by their equivalent Debye series formulations. An expression for the high-frequency backscattered field is proposed, and the monostatic radar cross section (RCS) of a large uniaxial Dielectric Sphere is calculated.
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Scattering from a large uniaxial Dielectric Sphere
2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), 2014Co-Authors: Mohsen Yazdani, Joseph R. Mautz, Luke Murphy, Ercument ArvasAbstract:The high frequency backscattering by a large uniaxial Dielectric Sphere is presented in this paper. Using the modified Watson method we transform the slowly convergent Mie series of the uniaxial Dielectric Sphere into a rapidly converging contour integral. The Mie series coefficients are then replaced by the geometric optics portion of the generalized Debye series for uniaxial Dielectric Sphere. With the aid of Debye's asymptotic formula, the contour integral is simplified and then computed using the saddle point method. A High frequency backscattering formula is proposed and the monostatic radar cross section (RCS) of a large uniaxial Dielectric Sphere is calculated. The results are compared with those computed using Lorentz-Mie theory.
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Electromagnetic plane wave scattering by a radially uniaxial Dielectric Sphere: Debye series solution
2014 IEEE MTT-S International Microwave Symposium (IMS2014), 2014Co-Authors: Mohsen Yazdani, Joseph R. Mautz, Luke Murphy, Ercument ArvasAbstract:In this paper, we examine the electromagnetic plane wave scattering by a uniaxial Dielectric Sphere using the generalized Debye series theory. With the aim of Debye series formulation, the generalized Mie series coefficients are replaced by infinite series of partial wave contributions that are diffracted, reflected and refracted following by p-1 internal reflections in the Sphere. In addition to exploring the bistatic Radar Cross Section (RCS) of the positive/negative uniaxial Dielectric Spheres using Lorenz-Mie theory, the first three terms of generalized Debye series are investigated and the results are applied to improve our understanding of scattering mechanism from a uniaxial Dielectric Sphere.
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transient electromagnetic scattering by a radially uniaxial Dielectric Sphere debye series mie series and ray tracing methods
Ph.D. Thesis, 2014Co-Authors: Mohsen YazdaniAbstract:Transient electromagnetic scattering by a radially uniaxial Dielectric Sphere is explored using three well-known methods: Debye series, Mie series, and ray tracing theory. In the first approach, the general solutions for the impulse and step responses of a uniaxial Sphere are evaluated using the inverse Laplace transformation of the generalized Mie series solution. Following high frequency scattering solution of a large uniaxial Sphere, the Mie series summation is split into the high frequency (HF) and low frequency terms where the HF term is replaced by its asymptotic expression allowing a significant reduction in computation time of the numerical Bromwich integral. In the second approach, the generalized Debye series for a radially uniaxial Dielectric Sphere is introduced and the Mie series coefficients are replaced by their equivalent Debye series formulations. The results are then applied to examine the transient response of each individual Debye term allowing the identification of impulse returns in the transient response of the uniaxial Sphere. In the third approach, the ray tracing theory in a uniaxial Sphere is investigated to evaluate the propagation path as well as the arrival time of the ordinary and extraordinary returns in the transient response of the uniaxial Sphere. This is achieved by extracting the reflection and transmission angles of a plane wave obliquely incident on the radially oriented air-uniaxial and uniaxial-air boundaries, and expressing the phase velocities as well as the refractive indices of the ordinary and extraordinary waves in terms of the incident angle, optic axis and propagation direction. The results indicate a satisfactory agreement between Debye series , Mie series and ray tracing methods. Transient electromagnetic scattering by a radially uniaxial Dielectric Sphere: Debye series, Mie series and ray tracing methods By Mohsen Yazdani M.S. IUST, 2009 Dissertation Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering Syracuse University August 2014 Copyright © Mohsen Yazdani August 2014 All Rights Reserved
Dimitrios C. Tzarouchis - One of the best experts on this subject based on the ideXlab platform.
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Can a Dielectric Sphere emulate the behavior of a surface impedance Sphereƒ
2019 URSI International Symposium on Electromagnetic Theory (EMTS), 2019Co-Authors: Dimitrios C. Tzarouchis, Pasi Ylä-oijala, Henrik Wallén, Ari SihvolaAbstract:We theoretically investigate whether a Dielectric Sphere can mimic the behavior of an equivalent surface impedance Sphere and we discuss some of the of emergent properties, such as cloaking (minimum scattering) and maximum absorption conditions.
-
light scattering by a Dielectric Sphere perspectives on the mie resonances
Applied Sciences, 2018Co-Authors: Dimitrios C. Tzarouchis, Ari SihvolaAbstract:Light scattering by a small spherical particle, a central topic for electromagnetic scattering theory, is here considered. In this short review, some of the basic features of its resonant scattering behavior are covered. First, a general physical picture is described by a full electrodynamic perspective, the Lorenz–Mie theory. The resonant spectrum of a Dielectric Sphere reveals the existence of two distinctive types of polarization enhancement: the plasmonic and the Dielectric resonances. The corresponding electrostatic (Rayleigh) picture is analyzed and the polarizability of a homogeneous spherical inclusion is extracted. This description facilitates the identification of the first type of resonance, i.e., the localized surface plasmon (plasmonic) resonance, as a function of the permittivity. Moreover, the electrostatic picture is linked with the plasmon hybridization model through the case of a step-inhomogeneous structure, i.e., a core–shell Sphere. The connections between the electrostatic and electrodynamic models are reviewed in the small size limit and details on size-induced aspects, such as the dynamic depolarization and the radiation reaction on a small Sphere are exposed through the newly introduced Mie–Pade approximative perspective. The applicability of this approximation is further expanded including the second type of resonances, i.e., the Dielectric resonances. For this type of resonances, the Mie–Pade approximation reveals the main character of the two different cases of resonances of either magnetic or electric origin. A unified picture is therefore described encompassing both plasmonic and Dielectric resonances, and the resonant conditions of all three different types are extracted as functions of the permittivity and the size of the Sphere. Lastly, the directional scattering behavior of the first two Dielectric resonances is exposed in a simple manner, namely the Kerker conditions for maximum forward and backscattering between the first magnetic and electric dipole contributions of a Dielectric Sphere. The presented results address several prominent functional features, aiming at readers with either theoretical or applied interest for the scattering aspects of a resonant Sphere.
-
resonant scattering characteristics of homogeneous Dielectric Sphere
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Dimitrios C. Tzarouchis, Pasi Ylaoijala, Ari SihvolaAbstract:In this paper, the classical problem of electromagnetic scattering by a single homogeneous Sphere is revisited. Main focus is the study of the scattering behavior as a function of the material contrast and the size parameters for all electric and magnetic resonances of a Dielectric Sphere. Specifically, the Pade approximants are introduced and utilized as an alternative system expansion of the Mie coefficients. Low order Pade approximants can give compact and physically insightful expressions for the scattering system and the enabled dynamic mechanisms. Higher order approximants are used for predicting accurately the resonant pole spectrum. These results are summarized into general pole formulae, covering up to fifth order magnetic and forth order electric resonances of a small Dielectric Sphere. Additionally, the connection between the radiative damping process and the resonant linewidth is investigated. The results obtained reveal the fundamental connection of the radiative damping mechanism with the maximum width occurring for each resonance. Finally, the suggested system ansatz is used for studying the resonant absorption maximum through a circuit-inspired perspective.
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Resonant Scattering Characteristics of Homogeneous Dielectric Sphere
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Dimitrios C. Tzarouchis, Pasi Ylä-oijala, Ari SihvolaAbstract:In the present article the classical problem of electromagnetic scattering by a single homogeneous Sphere is revisited. Main focus is the study of the scattering behavior as a function of the material contrast and the size parameters for all electric and magnetic resonances of a Dielectric Sphere. Specifically, the Pade approximants are introduced and utilized as an alternative system expansion of the Mie coefficients. Low order Pade approximants can give compact and physically insightful expressions for the scattering system and the enabled dynamic mechanisms. Higher order approximants are used for predicting accurately the resonant pole spectrum. These results are summarized into general pole formulae, covering up to fifth order magnetic and forth order electric resonances of a small Dielectric Sphere. Additionally, the connection between the radiative damping process and the resonant linewidth is investigated. The results obtained reveal the fundamental connection of the radiative damping mechanism with the maximum width occurring for each resonance. Finally, the suggested system ansatz is used for studying the resonant absorption maximum through a circuit-inspired perspective.
Li-gang Wang - One of the best experts on this subject based on the ideXlab platform.
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radiation forces of highly focused bessel gaussian beams on a Dielectric Sphere
Optik, 2008Co-Authors: Chengliang Zhao, Li-gang WangAbstract:Abstract The radiation force of highly focused Bessel–Gaussian beams (BGBs) on a Dielectric Sphere in the Rayleigh scattering regime is theoretically investigated. Numerical results demonstrate that the focused BGBs can be used to trap and manipulate the particles with the refractive index lower than that of the ambient. The radiation force caused by the low-order focused BGBs has been studied under different input parameters and different focus lengths of thin lens. The stability conditions of trapping the particles are also analyzed.
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dynamic radiation force of a pulsed gaussian beam acting on rayleigh Dielectric Sphere
Optics Express, 2007Co-Authors: Li-gang Wang, Chengliang ZhaoAbstract:We investigate the dynamic evolution of the radiation forces produced by the pulsed Gaussian beams acting on a Rayleigh Dielectric Sphere. We derive the analytical expressions for the scattering force and all components of the pondermotive force induced by the pulsed Gaussian beam. Our analysis shows that the radiation force can be greatly enhanced due to the effect of the short pulse duration, which leads to the enhancement of both the transverse and longitudinal radiation forces. And it is found that for the pulse with large pulse duration, it can be used for the stable trapping and manipulating the particle, while for the pulse with short pulse duration it may be used for guiding and moving the small Dielectric particle. Finally we discuss the stability condition of the effectively trapping and manipulating the particle by the pulsed beam.
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dynamic radiation force of a pulsed gaussian beam acting on a rayleigh Dielectric Sphere
arXiv: Optics, 2007Co-Authors: Li-gang Wang, Chengliang ZhaoAbstract:We investigate the dynamic evolution of the radiation forces produced by the pulsed Gaussian beams acting on a Rayleigh Dielectric Sphere. We derive the analytical expressions for the scattering force and all components of the ponderomotive force induced by the pulsed Gaussian beams. Our analysis shows that the radiation force, for both the transverse and longitudinal components, can be greatly enhanced as the pulse duration decreases. It is further found that for the pulse with long pulse duration, it can be used for the stable trapping and manipulating the particle, while for the pulse with short pulse duration it may be used for guiding and moving the small Dielectric particle. Finally we discuss the stability conditions of the effective manipulating the particle by the pulsed beam.
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effect of spatial coherence on radiation forces acting on a rayleigh Dielectric Sphere
Optics Letters, 2007Co-Authors: Li-gang Wang, Chengliang Zhao, Li-qin Wang, Shi-yao ZhuAbstract:We show that the radiation forces (RFs) on a Rayleigh Dielectric Sphere induced by a partially coherent light beam are greatly affected by the spatial coherence. We find that the magnitude of the RFs greatly decreases as the spatial coherence decreases and derive an inequality for the required correlation width σ0 (i.e., the spatial coherence of the beam) to stably trap the particles.
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Effect of Coherence on Radiation Forces acting on a Rayleigh Dielectric Sphere
Optics letters, 2007Co-Authors: Li-gang Wang, Chengliang Zhao, Li-qin Wang, Shi-yao ZhuAbstract:The radiation forces on a Rayleigh Dielectric Sphere induced by a partially coherent light beam are greatly affected by the coherence of the light beam. The magnitude of the radiation forces on a Dielectric Sphere near the focus point greatly decreases as the coherence decreases. For the light beam with good coherence, the radiation force may be used to trap a particle; and for the light beam with intermediate coherence, the radiation force may be used to guide and accelerate a particle.
Zhenli Xu - One of the best experts on this subject based on the ideXlab platform.
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accurate image charge method by the use of the residue theorem for core shell Dielectric Sphere
Journal of Chemical Physics, 2018Co-Authors: Jing Fu, Zhenli XuAbstract:An accurate image-charge method (ICM) is developed for ionic interactions outside a core-shell structured Dielectric Sphere. Core-shell particles have wide applications for which the theoretical investigation requires efficient methods for the Green’s function used to calculate pairwise interactions of ions. The ICM is based on an inverse Mellin transform from the coefficients of spherical harmonic series of the Green’s function such that the polarization charge due to Dielectric boundaries is represented by a series of image point charges and an image line charge. The residue theorem is used to accurately calculate the density of the line charge. Numerical results show that the ICM is promising in fast evaluation of the Green’s function, and thus it is useful for theoretical investigations of core-shell particles. This routine can also be applicable for solving other problems with spherical Dielectric interfaces such as multilayered media and Debye-Huckel equations.