2,562 research outputs found
Exact bidirectional X-wave solutions in fiber Bragg gratings
We find exact solutions describing bidirectional pulses propagating in fiber
Bragg gratings. They are derived by solving the coupled-mode theory equations
and are expressed in terms of products of modified Bessel functions with
algebraic functions. Depending on the values of the two free parameters the
general bidirectional X-wave solution can also take the form of a
unidirectional pulse. We analyze the symmetries and the asymptotic properties
of the solutions and also discuss about additional waveforms that are obtained
by interference of more than one solutions. Depending on their parameters such
pulses can create a sharp focus with high contrast
Supersymmetric Laser Arrays
The theoretical framework of supersymmetry (SUSY) aims to relate bosons and
fermions -- two profoundly different species of particles -- and their
interactions. While this space-time symmetry is seen to provide an elegant
solution to many unanswered questions in high-energy physics, its experimental
verification has so far remained elusive. Here, we demonstrate that, notions
from supersymmetry can be strategically utilized in optics in order to address
one of the longstanding challenges in laser science. In this regard, a
supersymmetric laser array is realized, capable of emitting exclusively in its
fundamental transverse mode. Our results not only pave the way towards devising
new schemes for scaling up radiance in integrated lasers, but also on a more
fundamental level, they could shed light on the intriguing synergy between
non-Hermiticity and supersymmetry
The modalities of Iranian soft power: from cultural diplomacy to soft war
Through exploring Iran's public diplomacy at the international level, this article demonstrates how the Islamic Republic's motives should not only be contextualised within the oft-sensationalised, material or âhardâ aspects of its foreign policy, but also within the desire to project its cultural reach through âsofterâ means. Iran's utilisation of culturally defined foreign policy objectives and actions demonstrates its understanding of soft power's potentialities. This article explores the ways in which Iran's public diplomacy is used to promote its soft power and craft its, at times, shifting image on the world stage
Electromagnetic wave scattering by a superconductor
The interaction between radiation and superconductors is explored in this
paper. In particular, the calculation of a plane standing wave scattered by an
infinite cylindrical superconductor is performed by solving the Helmholtz
equation in cylindrical coordinates. Numerical results computed up to
of Bessel functions are presented for different wavelengths
showing the appearance of a diffraction pattern.Comment: 3 pages, 3 figure
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