27,528 research outputs found
Interference and the lossless lossy beam splitter
By directing the input light into a particular mode it is possible to obtain
as output all of the input light for a beam splitter that is 50% absorbing.
This effect is also responsible for nonlinear quantum interference when two
photons are incident on the beam splitter.Comment: 10 pages, 2 figures, to appear in J. Mod. Op
Summary of Experimental Meson Physics
A summary of the present experimental status of meson physics is presented.
The presentation includes the new results presented at the MESON06 workshop, as
well as other recent experimental developments in the field.Comment: 15 pages, 6 figures, presented at 9th International Workshop on Meson
Production, Properties and Interaction, Krakow, Poland, June 200
Pinned modes in lossy lattices with local gain and nonlinearity
We introduce a discrete linear lossy system with an embedded "hot spot" (HS),
i.e., a site carrying linear gain and complex cubic nonlinearity. The system
can be used to model an array of optical or plasmonic waveguides, where
selective excitation of particular cores is possible. Localized modes pinned to
the HS are constructed in an implicit analytical form, and their stability is
investigated numerically. Stability regions for the modes are obtained in the
parameter space of the linear gain and cubic gain/loss. An essential result is
that the interaction of the unsaturated cubic gain and self-defocusing
nonlinearity can produce stable modes, although they may be destabilized by
finite amplitude perturbations. On the other hand, the interplay of the cubic
loss and self-defocusing gives rise to a bistability.Comment: Phys. Rev. E (in press
Calibration of shielded microwave probes using bulk dielectrics
A stripline-type near-field microwave probe is microfabricated for microwave
impedance microscopy. Unlike the poorly shielded coplanar probe that senses the
sample tens of microns away, the stripline structure removes the stray fields
from the cantilever body and localizes the interaction only around the
focused-ion beam deposited Pt tip. The approaching curve of an oscillating tip
toward bulk dielectrics can be quantitatively simulated and fitted to the
finite-element analysis result. The peak signal of the approaching curve is a
measure of the sample dielectric constant and can be used to study unknown bulk
materials.Comment: 10 pages, 3 figure
Effect of the stimulation level on the refractory behavior of the electrically stimulated auditory nerve
The refractory behavior of the electrically stimulated auditory nerve can be described by the recovery function, which plots the ECAP amplitude in response to a masker/probe stimulus pair as a function of the time interval (Masker Probe Interval, MPI) between the two stimuli. The recovery function is characterized by two time
intervals or periods: In the first interval (the Absolute Refractory Period, ARP), typically lasting for 300 to 400us, the neurons stimulated by the masker are in absolute refractory and unable to respond to the probe stimulus. As the MPI is gradually increased beyond the ARP, the stimulated neural population is increasingly able to respond to the probe stimulus (i.e. relative refractory) as the inhibitory effects of the masker diminishes.
This second interval (the Relative Refractory Period, RRP) can be characterized by the time constant of an asymptotically increasing exponential function (Morsnowski et al. 2006). This recovery time constant provides an indication of the neurons’ temporal characteristics.
Previous reports (e.g. Battmer et al. 2004) suggest that this time constant is affected by the stimulation level used to determine the recovery function. Such a dependency would make it difficult to characterize the refractory behavior of the stimulated neurons using the recovery function.
In this study, the refractory behavior of the electrically stimulated auditory nerve with respect to stimulation level was examined retrospectively. It was expected that increasing the stimulation level would result in more deterministic behavior
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