10,200 research outputs found
Spatially dispersive finite-difference time-domain analysis of sub-wavelength imaging by the wire medium slabs
In this paper, a spatially dispersive finite-difference time-domain (FDTD)
method to model wire media is developed and validated. Sub-wavelength imaging
properties of the finite wire medium slabs are examined. It is demonstrated
that the slab with its thickness equal to an integer number of half-wavelengths
is capable of transporting images with sub-wavelength resolution from one
interface of the slab to another. It is also shown that the operation of such
transmission devices is not sensitive to their transverse dimensions, which can
be made even comparable to the wavelength. In this case, the edge diffractions
are negligible and do not disturb the image formation.Comment: 14 pages, 13 figures, submitted to Optics Expres
Complementability of exponential systems
We prove that any incomplete system of complex exponentials in is a subset of some complete and minimal system of
exponentials. In addition, we prove analogous statement for systems of
reproducing kernels in de Branges spaces.Comment: 6 page
Radio emission from Air Showers. Comparison of theoretical approaches
While the fluorescence and the ground counter techniques for the detection of
ultra-high energy cosmic rays (UHECR) were being developed for decades, the
interest in the radio detection diminished after the initial experiments in the
1960s. As a result, the fluorescence and the surface array techniques are more
mature today, providing more reliable measurements of the primary cosmic
particle energy, chemical composition and the inelastic cross-section. The
advantages of the radio technique are 100 percent duty cycle and lower
deployment and operational costs. Thus, the radio technique can greatly
complement the fluorescence and the ground array detection and can also work
independently. With the ANITA balloon detector observing UHECRs and the success
of LOPES, CODALEMA and other surface radio detectors, the radio technique
received a significant boost in recent years. Reliable Monte Carlo (MC)
simulations are needed in order to obtain the energy and other parameters of
the primary cosmic ray particle from the radio observations. Several MC
techniques, like ZHairesS and the Endpoint Formalism, were proposed in recent
years. While they seem to reproduce some of the observed data quite well, there
is a divergence between the different approaches under certain conditions. In
this work we derive these approaches from Maxwells equations and prove their
identity under certain conditions as well as discuss their applicability to the
UHECR air showers and to a proposed experiment at SLAC.Comment: Accepted to AIP Proc. Suppl. January 15, 201
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