64 research outputs found
Enhanced soliton interactions by inhomogeneous nonlocality and nonlinearity
We address the interactions between optical solitons in the system with
longitudinally varying nonlocality degree and nonlinearity strength. We
consider a physical model describing light propagation in nematic liquid
crystals featuring a strongly nonlocal nonlinear response. We reveal that the
variation of the nonlocality and nonlinearity along the propagation direction
can substantially enhance or weaken the interaction between out-of-phase
solitons. This phenomenon manifests itself as a slowdown or acceleration of the
soliton collision dynamics in one-dimensional geometries or of the soliton
spiraling rate in bulk media. Therefore, one finds that by engineering the
nonlocality and nonlinearity variation rate one can control the output soliton
location.Comment: 22 pages, 5 figures, to appear in Physical Review
Route to nonlocality and observation of accessible solitons
We develop a general theory of spatial solitons in a liquid crystalline
medium exhibiting a nonlinearity with an arbitrary degree of effective
nonlocality. The model accounts the observability of "accessible solitons" and
establishes an important link with parametric solitons.Comment: 4 pages, 2 figure
Lattice-supported surface solitons in nonlocal nonlinear media
We reveal that lattice interfaces imprinted in nonlocal nonlinear media
support surface solitons that do not exist in other similar settings, including
interfaces of local and nonlocal uniform materials. We show the impact of
nonlocality on the domains of existence and stability of the surface solitons,
focusing on new types of dipole solitons residing partially inside the optical
lattice. We find that such solitons feature strongly asymmetric shapes and that
they are stable in large parts of their existence domain.Comment: 13 pages, 3 figures, to appear in Optics Letter
Upper threshold for stability of multipole-mode solitons in nonlocal nonlinear media
We address the stability of multipole-mode solitons in nonlocal Kerr-type
nonlinear media. Such solitons comprise several out-of-phase peaks packed
together by the forces acting between them. We discover that dipole-, triple-,
and quadrupole-mode solitons can be made stable, whereas all higher-order
soliton bound states are unstable.Comment: 15 pages, 4 figures, To appear in Optics Letter
Soliton mobility in nonlocal optical lattices
We address the impact of nonlocality in the physical features exhibited by
solitons supported by Kerr-type nonlinear media with an imprinted optical
lattice. We discover that nonlocality of nonlinear response can profoundly
affect the soliton mobility, hence all the related phenomena. Such behavior
manifests itself in significant reductions of the Peierls-Nabarro potential
with increase of the degree of nonlocality, a result that opens the rare
possibility in nature of almost radiationless propagation of highly localized
solitons across the lattice.Comment: 16 pages, 4 figure
Two dimensional modulational instability in photorefractive media
We study theoretically and experimentally the modulational instability of
broad optical beams in photorefractive nonlinear media. We demonstrate the
impact of the anisotropy of the nonlinearity on the growth rate of periodic
perturbations. Our findings are confirmed by experimental measurements in a
strontium barium niobate photorefractive crystal.Comment: 8 figure
Nonlinear management of the angular momentum of soliton clusters
We demonstrate an original approach to acquire nonlinear control over the
angular momentum of a cluster of solitary waves. Our model, derived from a
general description of nonlinear energy propagation in dispersive media, shows
that the cluster angular momentum can be adjusted by acting on the global
energy input into the system. The phenomenon is experimentally verified in
liquid crystals by observing power-dependent rotation of a two-soliton cluster.Comment: 4 pages, 3 figure
Multipole vector solitons in nonlocal nonlinear media
We show that multipole solitons can be made stable via vectorial coupling in
bulk nonlocal nonlinear media. Such vector solitons are composed of mutually
incoherent nodeless and multipole components jointly inducing a nonlinear
refractive index profile. We found that stabilization of the otherwise highly
unstable multipoles occurs below a maximum energy flow. Such threshold is
determined by the nonlocality degree.Comment: 13 pages, 3 figures, to appear in Optics Letter
Observation of optical spatial solitons in a highly nonlocal medium
We report on the observation and quantitative assessment of self-trapped
pulsating beams in a highly non-local nonlinear regime. The experiments were
conducted in nematic liquid crystals and allow a meaningful comparison with the
prediction of a scalar theory in the perturbative limit, while addressing the
need for beyond-paraxial analytical treatments.Comment: 16 pages, 3 figure
- …