32 research outputs found
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
Viscoelastic response of sonic band-gap materials
A brief report is presented on the effect of viscoelastic losses in a high
density contrast sonic band-gap material of close-packed rubber spheres in air.
The scattering properties of such a material are computed with an on-shell
multiple scattering method, properties which are compared with the lossless
case. The existence of an appreciable omnidirectional gap in the transmission
spectrum, when losses are present, is also reported.Comment: 5 pages, 4 figures, submitted to PR
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
Spectral and polarization effects in deterministically nonperiodic multilayers containing optically anisotropic and gyrotropic materials
Influence of material anisotropy and gyrotropy on optical properties of
fractal multilayer nanostructures is theoretically investigated. Gyrotropy is
found to uniformly rotate the output polarization for bi-isotropic multilayers
of arbitrary geometrical structure without any changes in transmission spectra.
When introduced in a polarization splitter based on a birefringent fractal
multilayer, isotropic gyrotropy is found to resonantly alter output
polarizations without shifting of transmission peak frequencies. The design of
frequency-selective absorptionless polarizers for polarization-sensitive
integrated optics is outlined
Scattering of elastic waves by periodic arrays of spherical bodies
We develop a formalism for the calculation of the frequency band structure of
a phononic crystal consisting of non-overlapping elastic spheres, characterized
by Lam\'e coefficients which may be complex and frequency dependent, arranged
periodically in a host medium with different mass density and Lam\'e
coefficients. We view the crystal as a sequence of planes of spheres, parallel
to and having the two dimensional periodicity of a given crystallographic
plane, and obtain the complex band structure of the infinite crystal associated
with this plane. The method allows one to calculate, also, the transmission,
reflection, and absorption coefficients for an elastic wave (longitudinal or
transverse) incident, at any angle, on a slab of the crystal of finite
thickness. We demonstrate the efficiency of the method by applying it to a
specific example.Comment: 19 pages, 5 figures, Phys. Rev. B (in press
Scattering of elastic waves by periodic arrays of spherical bodies
We develop a formalism for the calculation of the frequency band structure of a phononic crystal consisting of nonoverlapping elastic spheres, characterized by Lamé coefficients which may be complex and frequency dependent, arranged periodically in a host medium with different mass density and Lamé coefficients. We view the crystal as a sequence of planes of spheres, parallel to and having the two-dimensional periodicity of a given crystallographic plane, and obtain the complex band structure of the infinite crystal associated with this plane. The method allows one to calculate, also, the transmission, reflection, and absorption coefficients for an elastic wave (longitudinal or transverse) incident, at any angle, on a slab of the crystal of finite thickness. We demonstrate the efficiency of the method by applying it to a specific example. © 2000 The American Physical Society