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Effective-medium theories for electromagnetic constitutive parameters of particulate composite materials are theories of averages. Standard deviations are absent because of the lack of rigorous theories. But ensemble averages and standard…

Optics · Physics 2015-06-02 Craig F. Bohren , Xuerong Xiao , Akhlesh Lakhtakia

Optical properties of dust aggregates are important at various astrophysical environments. To find a reliable approximation method for optical properties of dust aggregates, we calculate the opacity and the asymmetry parameter of dust…

Earth and Planetary Astrophysics · Physics 2018-06-20 Ryo Tazaki , Hidekazu Tanaka

It is shown that the optical properties of an irregular porous grain with effective radius $a_{\rm eff}\lesssim 3\lambda$ (where $\lambda$ is the wavelength) can be well approximated by a ``spheroidal analog'': a spheroid with appropriate…

Astrophysics of Galaxies · Physics 2025-05-15 B. T. Draine

Interstellar grains may be composite collections of particles of distinct materials, including voids, agglomerated together. We determine the various optical cross sections of such composite grains, given the optical properties of each…

Astrophysics · Physics 2009-10-31 Nikolai V. Voshchinnikov , John S. Mathis

We study light scattering by spheres made of negative refractive index materials. We demonstrate that scattering efficiency of the light does not always obey the well-known Rayleigh's law $Q_{\rm sca}\sim1/\lambda^4$ for small values of…

Optics · Physics 2009-04-02 Andrey E. Miroshnichenko

We consider the time-harmonic elastic wave scattering from a general (possibly anisotropic) inhomogeneous medium with an embedded impenetrable obstacle. We show that the impenetrable obstacle can be effectively approximated by an isotropic…

Analysis of PDEs · Mathematics 2021-02-19 Zhengjian Bai , Huaian Diao , Hongyu Liu , Qingle Meng

The prevalence of clouds in currently observable exoplanetary atmospheres motivates the compilation and calculation of their optical properties. First, we present a new open-source Mie scattering code known as LX-MIE, which is able to…

Earth and Planetary Astrophysics · Physics 2017-12-06 Daniel Kitzmann , Kevin Heng

This paper provides a general framework for deriving effective material properties of one-dimensional, time-modulated systems of subwavelength resonators. It applies to subwavelength resonator systems with a general form of time-dependent…

Optics · Physics 2025-07-17 Habib Ammari , Jinghao Cao , Erik Orvehed Hiltunen , Liora Rueff

In the work, a modified effective medium theory is constructed for calculating the effective properties of thermoelectric composites with different values of percolation thresholds. It is shown that even at concentrations beyond the…

Materials Science · Physics 2020-06-23 Snarskii Andrei , Yuskevich Pavel

Considering light transport in disordered media, the medium is often treated as an effective medium requiring accurate evaluation of an effective refractive index. Because of its simplicity, the Maxwell-Garnett (MG) mixing rule is widely…

Optics · Physics 2023-06-01 Dominic T. Meiers , Georg von Freymann

The numerical analysis of elastic wave propagation in unbounded media may be difficult due to spurious waves reflected at the model artificial boundaries. This point is critical for the analysis of wave propagation in heterogeneous or…

Computational Physics · Physics 2010-09-07 Jean-François Semblat , Luca Lenti , Ali Gandomzadeh

An in-line hologram of a colloidal sphere can be analyzed with the Lorenz-Mie theory of light scattering to measure the sphere's three-dimensional position with nanometer-scale precision while also measuring its diameter and refractive…

Soft Condensed Matter · Physics 2020-12-29 Lauren E. Altman , Rushna Quddus , Fook Chiong Cheong , David G. Grier

Scattering of electromagnetic (EM) waves by many small particles (bodies) embedded in a homogeneous medium is studied. Physical properties of the particles are described by their boundary impedances. The limiting equation is obtained for…

Mathematical Physics · Physics 2011-01-18 A. G. Ramm

The purpose of this paper is to provide equations to model the evolution of effective diffusion over a Riemannian fiber bundle (under the hypothesis of infinite diffusion rate along compact fibers). These equations are obtained by…

Mathematical Physics · Physics 2015-02-24 Carlos Valero Valdes

The overall behavior of a 2D lattice of voids embedded in an anisotropic matrix is investigated in the limit of vanishing porosity f. An effective-medium model (of the Hashin-Shtrikman type) which accounts for elastic interactions between…

Materials Science · Physics 2008-09-19 Francois Willot , Yves-Patrick Pellegrini , Martin I. Idiart , Pedro Ponte Castaneda

The numerical analysis of elastic wave propagation in unbounded media may be difficult to handle due to spurious waves reflected at the model artificial boundaries. Several sophisticated techniques such as nonreflecting boundary conditions,…

Classical Physics · Physics 2010-09-06 Jean-François Semblat , Ali Gandomzadeh , Luca Lenti

Effective-medium theory pertains to the theoretical modelling of homogenization, which aims to replace an inhomogeneous structure of subwavelength-scale constituents with a homogeneous effective medium. The effective-medium theory is…

The efficiency of using intensity modulated light for estimation of scattering properties of a turbid medium and for ballistic photon discrimination is theoretically quantified in this article. Using the diffusion model for modulated photon…

Optics · Physics 2016-02-23 Swapnesh Panigrahi , Julien Fade , Hema Ramachandran , Mehdi Alouini

In this work, exact mathematical expansions for the intrinsic electromagnetic (EM) or optical cross-sections (i.e., extinction, scattering and absorption) for a pair of perfectly conducting circular cylinders in a homogeneous medium are…

Optics · Physics 2019-12-03 F. G. Mitri

Asymptotic solution to many-body wave scattering problem is given in the case of many small scatterers. The small scatterers can be particles whose physical properties are described by the boundary impedances, or they can be small…

Mathematical Physics · Physics 2011-01-25 A. G. Ramm