17 research outputs found
Transparent photonic band in metallodielectric nanostructures
Under certain conditions, a transparent photonic band can be designed into a
one-dimensional metallodielectric nanofilm structure. Unlike conventional pass
bands in photonic crystals, where the finite thickness of the structure affects
the transmission of electromagnetic fields having frequency within the pass
band, the properties of the transparent band are almost unaffected by the
finite thickness of the structure. In other words, an incident field at a
frequency within the transparent band exhibits 100% transmission independent of
the number of periods of the structure. The transparent photonic band
corresponds to excitation of pure eigenstate modes across the entire Bloch band
in structures possessing mirror symmetry. The conditions to create these modes
and thereby to lead to a totally transparent band phenomenon are discussed.Comment: To be published in Phys. Rev.
Characteristics of bound modes in coupled dielectric waveguides containing negative index media
We investigate the characteristics of guided wave modes in planar coupled
waveguides. In particular, we calculate the dispersion relations for TM modes
in which one or both of the guiding layers consists of negative index media
(NIM)-where the permittivity and permeability are both negative. We find that
the Poynting vector within the NIM waveguide axis can change sign and
magnitude, a feature that is reflected in the dispersion curves
Plasmonic Resonances and Electromagnetic Forces Between Coupled Silver Nanowires
We compute the electromagnetic response and corresponding forces between two
silver nanowires. The wires are illuminated by a plane wave which has the
electric field vector perpendicular to the axis of the wires, insuring that
plasmonic resonances can be excited. We consider a nontrivial square cross
section geometry that has dimensions on the order of , where
is the wavelength of the incident electromagnetic field. We find that
due to the plasmonic resonance, there occurs great enhancement of the direct
and mutual electromagnetic forces that are exerted on the nanowires. The
Lippman-Schwinger volume integral equation is implemented to obtain solutions
to Maxwell's equations for various and separation distances between
wires. The forces are computed using Maxwell's stress tensor and numerical
results are shown for both on and off resonant conditions