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Realizable artificial medium with negative permittivity,
permeability and refractive index are fabricated by
introducing inclusions significantly smaller than the
wavelengths of excitation into an archival host medium.
Negative refractive index media normally posses a small
degree of chirality associated with the split-rings. However
in order to enhance the chirality of the artificial media, the
split rings can be replaced by spirals.
Recent work has shown that well controlled chiral media
can be fabricated using available semiconductor techniques
that have been modified to produce these structures.
Specifically the glancing angle deposition technique
(GLAD) has been shown to be well suited to producing
these types of chiral structures.
Novel devices made from metamaterials that also possess
chirality are considered. When chiral properties are
included in a negative refractive index slab, with n = -1,
two rays are refracted in the slab. The distance between the
two corresponding focal lines is determined by the
magnitude of the chiral parameter. Thus this negative
refractive index lens can also be used to measure the chiral
parameter. At the focal lines small cross polarized
components also exist.
Based on the complete model expansion of the field at the
chiral-chiral (or free space-chiral) interface it is shown that
line sources also excite several species of lateral waves that
are associated with total internal reflection. Since the
refractive index is assumed to be negative, rays incident
upon the chiral slab at the critical angles for total internal
reflection, θ1 and θ2, are refracted parallel to the interface
in the backward direction, resulting in θR1 and θL1 equal to -90°. Thus the image and the source are on the same
side of the negative refractive index chiral slab and the
device behaves like a reflector.
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