454 research outputs found
Stable oscillating nonlinear beams in square-wave-biased-photorefractives
We demonstrate experimentally that in a centrosymmetric paraelectric
non-stationary boundary conditions can dynamically halt the intrinsic
instability of quasi-steady-state photorefractive self-trapping, driving beam
evolution into a stable oscillating two-soliton-state configuration.Comment: 3 pages, 4 figs, revtex os
Soliton electro-optic effects in paraelectrics
The combination of charge separation induced by the formation of a single
photorefractive screening soliton and an applied external bias field in a
paraelectric is shown to lead to a family of useful electro-optic guiding
patterns and properties.Comment: 3 pages, 5 figure
Beam Instabilities in the Scale Free Regime
The instabilities arising in a one-dimensional beam sustained by the
diffusive photorefractive nonlinearity in out-of-equilibrium ferroelectrics are
theoretically and numerically investigated. In the "scale-free model", in
striking contrast with the well-known spatial modulational instability, two
different beam instabilities dominate: a defocusing and a fragmenting process.
Both are independent of the beam power and are not associated to any specific
periodic pattern.Comment: 4 pages, 3 figure
Programming scale-free optics in disordered ferroelectrics
Using the history-dependence of a dipolar glass hosted in a
compositionally-disordered lithium-enriched potassium-tantalate-niobate
(KTN:Li) crystal, we demonstrate scale-free optical propagation at tunable
temperatures. The operating equilibration temperature is determined by previous
crystal spiralling in the temperature/cooling-rate phase-space
Relativistic regimes for dispersive shock-waves in non-paraxial nonlinear optics
We investigate the effect of non-paraxiality in the dynamics of dispersive
shock waves in the defocusing nonlinear Schroedinger equation. We show that the
problem can be described in terms of a relativistic particle moving in a
potential. Lowest order corrections enhance the wave-breaking and impose a
limit to the highest achievable spectrum in an amount experimentally testable.Comment: 6 pages, 4 figure
Subwavelength optical spatial solitons and three-dimensional localization in disordered ferroelectrics: towards metamaterials of nonlinear origin
We predict the existence of a novel class of multidimensional light
localizations in out-of-equilibrium ferroelectric crystals. In two dimensions,
the non-diffracting beams form at arbitrary low power level and propagate even
when their width is well below the optical wavelength. In three dimensions, a
novel form of subwavelength light bullets is found. The effects emerge when
compositionally disordered crystals are brought to their metastable glassy
state, and can have a profound impact on super-resolved imaging and ultra-dense
optical storage, while resembling many features of the so-called metamaterials,
as the suppression of evanescent waves.Comment: 4 pages, 3 figure
Collision and fusion of counterpropagating micron-sized optical beams in non-uniformly biased photorefractive crystals
We theoretically investigate collision of optical beams travelling in
opposite directions through a centrosymmetric photorefractive crystal biased by
a spatially non-uniform voltage. We analytically predict the fusion of
counterpropagating solitons in conditions in which the applied voltage is
rapidly modulated along the propagation axis, so that self-bending is
suppressed by the "restoring symmetry" mechanism. Moreover, when the applied
voltage is slowly modulated, we predict that the modified self-bending allows
conditions in which the two beams fuse together, forming a curved light-channel
splice.Comment: 12 page
- …