arXiv subjects

Lluis Torner

Publications and source records attributed to Lluis Torner.

At least 145 records · Page 8Linked to original sources

arXiv2007

Stability of vortex solitons in thermal nonlinear media with cylindrical symmetry

We analyze the salient features of vortex-ring solitons supported by cylindrically symmetric media with nonlocal thermal nonlinearity. We discover the existence of a maximum allowed topological charge for such vortex solitons to be stable on propagation: Only vortex-ring solitons with topological charge m<=2 are found to be stable. This remarkable result holds independently of the radius of the sample.

physics.optics↗

arXiv2007

Surface waves in defocusing thermal nonlinear optical media

We predict that the interface of materials with defocusing thermal nonlinearities support stable fundamental and higher-order surface waves when the opposite edges of the medium are maintained at different temperatures. Such surface waves exist due to the interplay between repulsion from the interface and the defocusing thermal nonlinearity that deflect light beams from the bulk of the medium toward its edges.

physics.optics↗

arXiv2007

Guiding-center solitons in rotating potentials

We demonstrate that rotating quasi-one-dimensional potentials, periodic or parabolic, support solitons in settings where they are otherwise impossible. Ground-state and vortex solitons are found in defocusing media, if the rotation frequency exceeds a critical value. The revolving periodic potentials exhibit the strongest stabilization capacity at a finite optimum value of their strength, while the rotating parabolic trap features a very sharp transition to stability with the increase of rotation frequency.

physics.optics↗

arXiv2007

Soliton emission in amplifying optical lattice surfaces

We address surface solitons supported by the interface of optical lattices imprinted in saturable media with surface-localized gain. The nonlinearity saturation puts restrictions on the maximal energy flow carried by surface solitons. As a consequence, the presence of thin amplifying layer near the surface results in the controllable emission of solitons towards the lattice at angles depending on the amplification rate and on lattice depth.

physics.optics↗

arXiv2007

Observation of higher-order solitons in defocusing waveguide arrays

We observe experimentally higher-order solitons in waveguide arrays with defocusing saturable nonlinearity. Such solitons can comprise several in-phase bright spots and are stable above a critical power threshold. We elucidate the impact of the nonlinearity saturation on the domains of existence and stability of the observed complex soliton states.

physics.optics↗

arXiv2007

Gray spatial solitons in nonlocal nonlinear media

We study gray solitons in nonlocal nonlinear media and show that they are stable and can form bound states. We reveal that gray soliton velocity depends on the nonlocality degree, and that it can be drastically reduced in highly nonlocal media. This is in contrast to the case of local media, where the maximal velocity is dictated solely by the asymptotic soliton amplitude.

physics.optics↗

arXiv2006

Surface lattice kink solitons

We predict theoretically that surface of an optical lattice imprinted in defocusing nonlinear media can support shock, or kink waves. Such new surface waves contain a modulationally stable pedestal and are strongly localized at the edge of the optical lattice due to Bragg-type reflection. The kink steepness and localization degree can be controlled by the lattice depth. We found two types of kinks, which exhibit distinct stability properties for each finite gap in the lattice spectrum. Our findings open the way to experimental observation of optical surface kink waves.

physics.optics↗

arXiv2006

Vector soliton fission by reflection at nonlinear interfaces

We address the reflection of vector solitons, comprising several components that exhibit multiple field oscillations, at the interface between two nonlinear media. We reveal that reflection causes fission of the input signal into sets of solitons propagating at different angles. We find that the maximum number of solitons that arises upon the fission is given by the number of field oscillations in the highest-order input vector soliton.

physics.optics↗

arXiv2006

Asymmetric matter-wave solitons at nonlinear interfaces

We predict the existence and study the basic properties of strongly asymmetric matter wave solitons that form at the interface produced by regions with different inter-atomic interaction strengths in pancake Bose-Einstein condensates. We address several types of surface solitons featuring topologically complex structures, including vortex and dipole-mode solitons. We found that the soliton become significantly asymmetric for high number of particles in the condensate. Yet, we reveal that under suitable conditions, that we elucidate, even such strongly asymmetric dipole and vortex solitons can be dynamically stable over wide regions of their existence domains.

cond-mat.mtrl-sci↗

arXiv2006

Matter-wave soliton control in optical lattices with topological dislocations

We address the concept of guiding and transporting matter-wave solitons along the channels of optical lattices made by interference patterns of beams containing topological wavefront dislocations. The local lattice distortions that occur around the dislocations cause solitons to move along reconfigurable paths, a phenomenon that may be used for controlled all-optical manipulation of Bose-Einstein condensates. Multiple dislocations form traps that can capture and hold moving solitons.

physics.optics↗

arXiv2006

Two-dimensional multi-pole solitons in nonlocal nonlinear media

We present the experimental observation of scalar multi-pole solitons in highly nonlocal nonlinear media, including dipole-, tri-pole, quadru-pole, and necklace-type solitons, organized as arrays of out-of-phase bright spots. These complex solitons are meta-stable, but with a large parameters range where the instability is weak, enabling their experimental observation.

physics.optics↗

arXiv2006

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.

physics.optics↗

arXiv2006

Vector mixed-gap surface solitons

We elucidate the properties of mixed-gap vector surface solitons supported by the interface between a uniform medium and an optical lattice imprinted in a Kerr-type nonlinear media. The components of such mixed-gap solitons emerge from different gaps of lattice spectrum and their mutual trapping results in the formation of stable vector states. The unstable soliton component is stabilized by the cross-coupling with the stable component. We show that vector mixed-gap surface solitons exhibit a new combination of properties of vectorial surface waves and gap solitons.

physics.optics↗

arXiv2006

Generation of surface soliton arrays

We discover that at the edge of optical lattice imprinted in saturable nonlinear media one-dimensional surface solitons exist only within a band of light intensities, and that they cease to exist when the lattice depth exceeds an upper threshold. We also reveal the generation of arrays of two-dimensional surface solitons mediated by transverse modulational instability of one-dimensional solitons, a process that is found to exhibit specific features associated to properties of the optical lattice.

physics.optics↗

arXiv2006

Soliton control in fading optical lattices

We predict new phenomena, such as soliton steering and soliton fission, in optical lattices that fade away exponentially along the propagation direction. Such lattices, featuring tunable decay rates, arise in photorefractive crystals in the wavelength range 360-400 nm. We show that the predicted phenomena offer different opportunities for soliton control.

physics.optics↗

arXiv2006

Stabilization of vector soliton complexes in nonlocal nonlinear media

We introduce vector soliton complexes in nonlocal Kerr-type nonlinear media. We discover that under proper conditions the combination of nonlocality and vectorial coupling has a remarkable stabilizing action on multi-humped solitons. In particular, we find that stable bound states featuring several field oscillations in each soliton component do exist. This affords stabilization of vector soliton trains incorporating large number of humps, a class of structures known to self-destroy via strong instabilities in scalar settings.

nlin.PS↗

arXiv2006

Gap solitons supported by optical lattices in photorefractive crystals with asymmetric nonlocality

We address the impact of asymmetric nonlocal diffusion nonlinearity on the properties of gap solitons supported by photorefractive crystal with an imprinted optical lattice. We reveal how the asymmetric nonlocal response alters the domains of existence and the stability of solitons originating from different gaps. We find that in such media gap solitons cease to exist above a threshold of the nonlocality degree. We discuss how the interplay between nonlocality and lattice strength modifies the gap soliton mobility.

nlin.PS↗

arXiv2006

Multipole-mode surface solitons

We discover multipole-mode solitons supported by the surface between two distinct periodic lattices imprinted in Kerr-type nonlinear media. Such solitons are possible because the refractive index modulation at both sides of the interface glues together their out-of-phase individual constituents. Remarkably, we find that the new type of solitons may feature highly asymmetric shapes and yet they are stable over wide domains of their existence, a rare property to be attributed to their surface nature.

physics.optics↗