15,474 research outputs found
Circular dichroism induced by Fano resonances in planar chiral oligomers
We present a general theory of circular dichroism in planar chiral
nanostructures with rotational symmetry. It is demonstrated, analytically, that
the handedness of the incident field's polarization can control whether a
nanostructure induces either absorption or scattering losses, even when the
total optical loss (extinction) is polarization-independent. We show that this
effect is a consequence of modal interference so that strong circular dichroism
in absorption and scattering can be engineered by combining Fano resonances
with planar chiral nanoparticle clusters.Comment: 12 pages, 5 figure
Interplay of magnetic responses in all-dielectric oligomers to realize magnetic Fano resonances
We study the interplay between collective and individual optically-induced
magnetic responses in quadrumers made of identical dielectric nanoparticles.
Unlike their plasmonic counterparts, all-dielectric nanoparticle clusters are
shown to exhibit multiple dimensions of resonant magnetic responses that can be
employed for the realization of anomalous scattering signatures. We focus our
analysis on symmetric quadrumers made from silicon nanoparticles and verify our
theoretical results in proof-of-concept radio frequency experiments
demonstrating the existence of a novel type of magnetic Fano resonance in
nanophotonics.Comment: 20 pages, 7 figure
The Uncertainty of Fluxes
In the ordinary quantum Maxwell theory of a free electromagnetic field,
formulated on a curved 3-manifold, we observe that magnetic and electric fluxes
cannot be simultaneously measured. This uncertainty principle reflects torsion:
fluxes modulo torsion can be simultaneously measured. We also develop the
Hamilton theory of self-dual fields, noting that they are quantized by
Pontrjagin self-dual cohomology theories and that the quantum Hilbert space is
Z/2-graded, so typically contains both bosonic and fermionic states.
Significantly, these ideas apply to the Ramond-Ramond field in string theory,
showing that its K-theory class cannot be measured.Comment: 33 pages; minor modifications for publication in Commun. Math. Phy
Microprogram scheme for automatic recovery from computer error
Microprogram scheme enables computer to recover from failure in one of its two central processing units during time duration of instruction in which failure occurs. Microprogram advantages include - /1/ built-in interpretive capability, /2/ selection of processing interrupts by priority, and /3/ economical use of bootstrap sequence
Reusable Agena study. Volume 2: Technical
The application of the existing Agena vehicle as a reusable upper stage for the space shuttle is discussed. The primary objective of the study is to define those changes to the Agena required for it to function in the reusable mode in the 100 percent capture of the NASA-DOD mission model. This 100 percent capture is achieved without use of kick motors or stages by simply increasing the Agena propellant load by using optional strap-on-tanks. The required shuttle support equipment, launch and flight operations techniques, development program, and cost package are also defined
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