476 research outputs found
Counterposition and negative phase velocity in uniformly moving dissipative materials
The Lorentz transformations of electric and magnetic fields were implemented
to study (i) the refraction of linearly polarized plane waves into a half-space
occupied by a uniformly moving material, and (ii) the traversal of linearly
polarized Gaussian beams through a uniformly moving slab. Motion was taken to
occur tangentially to the interface(s) and in the plane of incidence. The
moving materials were assumed to be isotropic, homogeneous, dissipative
dielectric materials from the perspective of a co-moving observer. Two
different moving materials were considered: from the perspective of a co-moving
observer, material A supports planewave propagation with only positive phase
velocity, whereas material B supports planewave propagation with both positive
and negative phase velocity, depending on the polarization state. For both
materials A and B, the sense of the phase velocity and whether or not
counterposition occurred, as perceived by a nonco-moving observer, could be
altered by varying the observer's velocity. Furthermore, the lateral position
of a beam upon propagating through a uniformly moving slab made of material A,
as perceived by a nonco-moving observer, could be controlled by varying the
observer's velocity. In particular, at certain velocities, the transmitted beam
emerged from the slab laterally displaced in the direction opposite to the
direction of incident beam. The transmittances of a uniformly moving slab made
of material B were very small and the energy density of the transmitted beam
was largely concentrated in the direction normal to the slab, regardless of the
observer's velocity
A new condition to identify isotropic dielectric-magnetic materials displaying negative phase velocity
The derivation of a new condition for characterizing isotropic
dielectric-magnetic materials exhibiting negative phase velocity, and the
equivalence of that condition with previously derived conditions, are
presented.Comment: 4 page
Scattering loss in electro-optic particulate composite materials
The effective permittivity dyadic of a composite material containing
particulate constituent materials with one constituent having the ability to
display the Pockels effect is computed, using an extended version of the
strong-permittivity-fluctuation theory which takes account of both the
distributional statistics of the constituent particles and their sizes.
Scattering loss, thereby incorporated in the effective electromagnetic response
of the homogenized composite material, is significantly affected by the
application of a low-frequency (dc) electric field
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