Acoustic properties of colloidal crystals

We present a systematic study of the frequency band structure of acoustic waves in crystals consisting of nonoverlapping solid spheres in a fluid. We consider colloidal crystals consisting of polystyrene spheres in water, and an opal consisting of close-packed silica spheres in air. The opal exhibits an omnidirectional frequency gap of considerable width; the colloidal crystals do not. The physical origin of the bands are discussed for each case in some detail. We present also results on the transmittance of finite slabs of the above crystals.Comment: 7 pages, 9 figures, prb approve

Effective-medium description of dielectric-chiral photonic crystals

The effective medium behavior of dielectric chiral composite photonic crystals in the long-wavelength limit of electromagnetic (EM) waves was examined. The study used the results of calculations of the EM response of photonic crystals of chiral spheres in conjunction with an effective medium approach to chiral composites. The effective EM response of the crystal was then compared with the exact one. In addition, a discussion of the concept of homogenization in the frequency range extending up to the first band gap of the EM spectrum is provided

Photonic crystals of chiral spheres

We examined the properties of photonic crystals that consist of nonoverlapping chiral spheres in a dielectric medium. We considered the effect of the chiral property of the spheres on the frequency band structure of the electromagnetic field in the crystal and on the transmittance properties of a slab of the crystal, and we estimated the optical activity of the crystal. © 1999 Optical Society of America

Birefringent phononic structures

Within the framework of elastic anisotropy, caused in a phononic crystal due to low crystallographic symmetry, we adopt a model structure, already introduced in the case of photonic metamaterials, and by analogy, we study the effect of birefringence and acoustical activity in a phononic crystal. In particular, we investigate its low-frequency behavior and comment on the factors which determine chirality by reference to this model. © 2014 Author(s)

Absolute spectral gaps for infrared light and hypersound in three-dimensional metallodielectric phoxonic crystals

By means of full electrodynamic and elastodynamic multiple-scattering calculations we study the optical and acoustic properties of three-dimensional lattices of metallic nanospheres implanted in a dielectric host. Our results show that such structures exhibit omnidirectional spectral gaps for both telecom infrared light and hypersound, with relatively low absorptive losses. This class of dual (phoxonic) band-gap materials is an essential step toward the hypersonic modulation of light and could lead to the development of efficient acousto-optical devices. © 2010 American Institute of Physics

Acoustic properties of colloidal crystals

We present a systematic study of the frequency band structure of acoustic waves in crystals consisting of nonoverlapping solid spheres in a fluid. We consider colloidal crystals consisting of polystyrene spheres in water, and an opal consisting of close-packed silica spheres in air. The opal exhibits an omnidirectional frequency gap of considerable width; the colloidal crystals do not. The physical origin of the bands are discussed for each case in some detail. We also present results on the transmittance of finite slabs of the above crystals

The layer multiple-scattering method applied to phononic crystals

After a brief description of the layer multiple-scattering method as applied to phononic crystals, we present some results obtained by this method, relating to: crystals of polystyrene spheres in water; crystals of silica spheres in air; and crystals of steel spheres in polyester. We relate the transmission characteristics of slabs of these materials to the complex band structure of the corresponding infinite crystals. We emphasize aspects of the underlying physics which have not been discussed previously. © by Oldenbourg Wissenschaftsverlag

A layer-multiple-scattering method for phononic crystals and heterostructures of such

We present a computer program to calculate the frequency band structure of an infinite phononic crystal, and the transmission, reflection and absorption of elastic waves by a slab of this crystal. The crystal consists of a stack of identical slices parallel to a given surface; the slice may consist of multilayers of non-overlapping spheres of given periodicity parallel to the surface and homogeneous plates. The elastic coefficients of the various components of the crystal may be complex functions of the frequency

On wave propagation in inhomogeneous systems

We present a theory of electron, electromagnetic, and elastic wave propagation in systems consisting of non-overlapping scatterers in a host medium. The theory provides a framework for a unified description of wave propagation in three-dimensional periodic structures, finite slabs of layered structures, and systems with impurities: isolated impurities, impurity aggregates, or randomly distributed impurities. We point out the similarities and differences between the different cases considered, and discuss the numerical implementation of the formalism. © 2001 Elsevier Science B.V

Elastodynamic response of three-dimensional phononic crystals using laser Doppler vibrometry

The elastodynamic response of finite 3D phononic structures is analyzed by means of comparing experimental findings obtained through a laser Doppler vibrometry-based methodology and theoretical computations performed with the layer-multiple-scattering method. The recorded frequency-gap spectrum of the phononic slabs exhibited a good agreement of theory to experiment. Along these lines, a newly developed technique, based on laser Doppler vibrometry, has been proposed and validated for the dispersion efficiency in 3D phononic metamaterials. © 2019 IOP Publishing Ltd