Biomedical subjects

Lluis Torner

Publications and source records attributed to Lluis Torner.

10 recordsLinked to original sources

PubMed2003

Deflection of quadratic solitons at edge dislocations.

We report the observation of deflection of optical solitons generated in the frequency doubling of light beams containing edgelike topological amplitude and phase dislocations. The angular deflection of the solitons was found to be controllable through the position of the dislocation. The experiments were conducted near phase matching in a bulk potassium titanyl phosphate crystal pumped with picosecond light pulses at 1064 nm.

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PubMed2003

Arresting wave collapse by wave self-rectification.

We put forward a mechanism for tailoring, and even arresting, the collapse of wave packets in nonlinear media, whose dynamics is governed by nonlocal two-dimensional nonlinear Schrödinger-like equations. The key ingredient of the scheme is the self-generation of nonlocal nonlinearities mediated by wave rectification.

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PubMed2003

Two-dimensional cnoidal waves in Kerr-type saturable nonlinear media.

We report theoretically the existence, classification, and basic properties of families of stationary two-dimensional cnoidal-type waves in bulk Kerr-type saturable nonlinear media. The families of two-dimensional cnoidal-type wave solutions are shown to exhibit richer features than their known one-dimensional counterparts. At low- and high-energy flows, the cnoidal patterns are predicted to be robust enough to be observable experimentally.

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PubMed2003

Observation of multiple soliton generation mediated by amplification of asymmetries.

We report the experimental observation of the formation of multiple optical quadratic solitons in a process mediated by the amplification of minute asymmetries in the diffraction properties of the input light. Experiments were conducted in phase-matched second-harmonic generation in a bulk crystal of periodically poled potassium titanyl phosphate pumped at 1064 nm. The different mechanisms that influence the process were investigated numerically, and the pulsed nature of the pump light was found to play a key role in the observed light distributions.

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PubMed2003

Soliton "molecules": robust clusters of spatiotemporal optical solitons.

We show how to generate robust self-sustained clusters of soliton bullets-spatiotemporal (optical or matter-wave) solitons. The clusters carry an orbital angular momentum being supported by competing nonlinearities. The "atoms" forming the "molecule" are fully three-dimensional solitons linked via a staircaselike macroscopic phase. Recent progress in generating atomic-molecular coherent mixing in the Bose-Einstein condensates might open potential scenarios for the experimental generation of these soliton molecules with matter waves.

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PubMed2003

Quadratic spatial solitons in periodically poled KTiOPO4.

The evolution of fundamental beams into quadratic spatial solitons was investigated in a periodically poled bulk KTiOPO4 crystal near and at phase matching. Various soliton properties, such as trapping efficiency as a function of phase mismatch, poling-induced walk-off, and the effects of pulse width, beam width, and input beam quality, were measured. Effects attributed to the presence of cubic nonlinearities were also observed.

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PubMed2002

Robust propagation of two-color soliton clusters supported by competing nonlinearities.

We reveal numerically the remarkably robust propagation of quasistationary two-color soliton clusters in media with competing quadratic and cubic nonlinearities. We predict that such clusters carrying nonzero angular momentum can propagate over any practically feasible crystal length before they decay, even in the presence of input random perturbations.

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PubMed2002

Globally linked vortex clusters in trapped wave fields.

We put forward the existence of a rich variety of fully stationary vortex structures, termed H clusters, made of an increasing number of vortices nested in paraxial wave fields confined by trapping potentials. However, we show that the constituent vortices are globally linked, rather than products of independent vortices. Also, they always feature a monopolar global wave front and exist in nonlinear systems, such as the Bose-Einstein condensates. Clusters with multipolar global wave fronts are nonstationary or, at best, flipping.

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PubMed2002

Superposition of noncoaxial vortices in parametric wave mixing.

In this paper we present a comprehensive study of the dynamics of screw phase dislocations under conditions of noncoaxial parametric three-wave mixing in the pump low-depletion regime. Under such conditions the signal and idler fields couple and so, the fields' properties change through propagation in the nonlinear crystal. We present an analytical model and a comprehensive study of the vortical features of the resulting field. The model is compared with the numerical solutions of the full equations. It is shown that by changing the relative amplitude and phase of the initial fields, one can control the domains where creation and annihilation of vortex-antivortex twins lead to different vortex content. We show that the effects studied here are relevant to a variety of physical systems. In particular, we show that the same phenomena are expected to occur in gyrotropic media and photonic crystals.

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PubMed2001

Management of the angular momentum of light: preparation of photons in multidimensional vector states of angular momentum.

We put forward schemes to prepare photons in multidimensional vector states of orbital angular momentum. We show realizable light distributions that yield prescribed states with finite or infinite normal modes. In particular, we show that suitable light vortex pancakes allow the add-drop of specific vector projections. We suggest that such photons might allow the generation of engineered quNits in multidimensional quantum information systems.

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