Articles de revista
http://hdl.handle.net/2117/3271
20161207T21:02:19Z

Selfsplitting of beams into spatial solitons in planar waveguides made of quadratic nonlinear media
http://hdl.handle.net/2117/97901
Selfsplitting of beams into spatial solitons in planar waveguides made of quadratic nonlinear media
Perez, J; Torner Sabata, Lluís
The propagation of intense light beams in planar optical waveguides made of quadratic nonlinear media under conditions for secondharmonic generation is investigated. It is shown numerically that under appropriate conditions, input light beams break up into several spatial solitons that separate from each other and exit the waveguide at different positions. This paper reports the results of a series of numerical experiments and analytical investigations that were performed to elucidate the dynamics of the selfsplitting process and discusses the implications of the results to the implementation of an eigenvalue switching device.
20161207T16:59:46Z
Perez, J
Torner Sabata, Lluís
The propagation of intense light beams in planar optical waveguides made of quadratic nonlinear media under conditions for secondharmonic generation is investigated. It is shown numerically that under appropriate conditions, input light beams break up into several spatial solitons that separate from each other and exit the waveguide at different positions. This paper reports the results of a series of numerical experiments and analytical investigations that were performed to elucidate the dynamics of the selfsplitting process and discusses the implications of the results to the implementation of an eigenvalue switching device.

Soliton evolution in quasiphasematched secondharmonic generation
http://hdl.handle.net/2117/97897
Soliton evolution in quasiphasematched secondharmonic generation
Torner Sabata, Lluís; Stegeman, G I
We investigate the formation and evolution of spatial solitons with light beams propagating in quadratic nonlinear media under conditions for secondharmonic generation in quasiphasematched samples. We study the properties of the solitons as a function of the periodicity of the domainreversal process involved in the quasiphasematching techniques, and we show the effects introduced by random shifts of the nominal domain length.
© 1997 Optical Society of America
20161207T16:41:51Z
Torner Sabata, Lluís
Stegeman, G I
We investigate the formation and evolution of spatial solitons with light beams propagating in quadratic nonlinear media under conditions for secondharmonic generation in quasiphasematched samples. We study the properties of the solitons as a function of the periodicity of the domainreversal process involved in the quasiphasematching techniques, and we show the effects introduced by random shifts of the nominal domain length.
© 1997 Optical Society of America

Asymmetrical splitting of higherorder optical solitons induced by quintic nonlinearity
http://hdl.handle.net/2117/97895
Asymmetrical splitting of higherorder optical solitons induced by quintic nonlinearity
Artigas García, David; Torner Sabata, Lluís; Pérez Torres, Juan; Akhmediev, Juan P Torres I Nail N
We address the effect of quintic nonlinearities in the propagation of optical solitons in cubic nonlinear media. Our focus is on the decay of higherorder solitons in the presence of selfdefocusing quintic perturbations. We show that, in spite of the fact that the governing evolution equations are symmetric, the quintic nonlinearity produces the asymmetrical selfsplitting of the solitons. We study in detail the selfsplitting process and compare the results with the soliton evolution with selffocusing quintic perturbations.
20161207T16:37:01Z
Artigas García, David
Torner Sabata, Lluís
Pérez Torres, Juan
Akhmediev, Juan P Torres I Nail N
We address the effect of quintic nonlinearities in the propagation of optical solitons in cubic nonlinear media. Our focus is on the decay of higherorder solitons in the presence of selfdefocusing quintic perturbations. We show that, in spite of the fact that the governing evolution equations are symmetric, the quintic nonlinearity produces the asymmetrical selfsplitting of the solitons. We study in detail the selfsplitting process and compare the results with the soliton evolution with selffocusing quintic perturbations.

Secondharmonic generation by intense beams containing phase dislocations:selfbreaking into sets of solitons
http://hdl.handle.net/2117/97893
Secondharmonic generation by intense beams containing phase dislocations:selfbreaking into sets of solitons
Petrov, D V; Torner Sabata, Lluís
Secondharmonic generation of light in bulk quadratic nonlinear media with intense input beams containing phase dislocations is studied numerically under conditions for TypeI phasematching. We investigate how, above a threshold light intensity, the input beams selfsplit along the azimuthal direction into a pattern of separate beams which then form a set of spatial solitons. The mechanism of such a behaviour is the azimuthal modulational instability of the ringshaped, mutually trapped fundamental and secondharmonic beams containing the phase dislocations.
20161207T16:12:47Z
Petrov, D V
Torner Sabata, Lluís
Secondharmonic generation of light in bulk quadratic nonlinear media with intense input beams containing phase dislocations is studied numerically under conditions for TypeI phasematching. We investigate how, above a threshold light intensity, the input beams selfsplit along the azimuthal direction into a pattern of separate beams which then form a set of spatial solitons. The mechanism of such a behaviour is the azimuthal modulational instability of the ringshaped, mutually trapped fundamental and secondharmonic beams containing the phase dislocations.

Walking solitons in type II secondharmonic generation
http://hdl.handle.net/2117/97892
Walking solitons in type II secondharmonic generation
Mihalache, Dumitru; Mazilu, D; Crasovan, L C; Torner Sabata, Lluís
We find the families of spatial walking solitons propagating in quadratic nonlinear media under conditions for type II secondharmonic generation in the presence of Poynting vector walkoff between the interacting beams. The analytical stability criterion for these threeparameter vector solitons is established. We study the shape and general properties of the solitons and their stability on propagation. It is found that the stationary solutions are stable at moderate positive phase mismatch. At phase matching and negative phase mismatch there are some unstable solutions near the cutoff.
20161207T16:08:13Z
Mihalache, Dumitru
Mazilu, D
Crasovan, L C
Torner Sabata, Lluís
We find the families of spatial walking solitons propagating in quadratic nonlinear media under conditions for type II secondharmonic generation in the presence of Poynting vector walkoff between the interacting beams. The analytical stability criterion for these threeparameter vector solitons is established. We study the shape and general properties of the solitons and their stability on propagation. It is found that the stationary solutions are stable at moderate positive phase mismatch. At phase matching and negative phase mismatch there are some unstable solutions near the cutoff.

Walking solitons
http://hdl.handle.net/2117/97891
Walking solitons
Torner Sabata, Lluís; Santos Blanco, M. Concepción; Mihalache, Dumitru; Mazilu, D; Crasovan, L C
By and large, optical
20161207T16:04:24Z
Torner Sabata, Lluís
Santos Blanco, M. Concepción
Mihalache, Dumitru
Mazilu, D
Crasovan, L C
By and large, optical

A game of billiards with spatial solitary waves in ktp
http://hdl.handle.net/2117/97872
A game of billiards with spatial solitary waves in ktp
Torruellas, W; Torner Sabata, Lluís
20161207T14:02:23Z
Torruellas, W
Torner Sabata, Lluís

On fluctuations in interfacial fluid systems
http://hdl.handle.net/2117/97813
On fluctuations in interfacial fluid systems
Torner Sabata, Lluís; Rubí Capaceti, José Miguel; Díaz Guilera, Albert
We study the propagation of the temperature fluctuations in a system in the presence of an interface. Such fluctuations originate from surface noise sources which are introduced through the random parts of the interfacial currents which satisfy fluctuationdissipation theorems. The formal solution for the fluctuations in the media and at the interface is given and from it we compute and analyze the prepagators. In particular we find that such quantities depend on three characteristics frequencies that are responsible for their peculiar behaviour. The temperature correlation function exhibits 1/f noise in a particular frequency range.
20161205T17:39:06Z
Torner Sabata, Lluís
Rubí Capaceti, José Miguel
Díaz Guilera, Albert
We study the propagation of the temperature fluctuations in a system in the presence of an interface. Such fluctuations originate from surface noise sources which are introduced through the random parts of the interfacial currents which satisfy fluctuationdissipation theorems. The formal solution for the fluctuations in the media and at the interface is given and from it we compute and analyze the prepagators. In particular we find that such quantities depend on three characteristics frequencies that are responsible for their peculiar behaviour. The temperature correlation function exhibits 1/f noise in a particular frequency range.

Mode count in planar gradedindex waveguides
http://hdl.handle.net/2117/97811
Mode count in planar gradedindex waveguides
Torner Sabata, Lluís; Canal Bienzobas, Fernando; March, L. de
The cutoff properties for the TE modes of planar gradedindex waveguides have been analysed in terms of the usual normalised waveguide parameters by using the multilayer technique. High accuracy has been achieved. The refractive index distributions more often used to model the actual profiles obtained by the usual fabrication techniques have been considered.
20161205T17:02:58Z
Torner Sabata, Lluís
Canal Bienzobas, Fernando
March, L. de
The cutoff properties for the TE modes of planar gradedindex waveguides have been analysed in terms of the usual normalised waveguide parameters by using the multilayer technique. High accuracy has been achieved. The refractive index distributions more often used to model the actual profiles obtained by the usual fabrication techniques have been considered.

Soliton excitation and mutual locking of light beams in bulk quadratic nonlinear crystals
http://hdl.handle.net/2117/97810
Soliton excitation and mutual locking of light beams in bulk quadratic nonlinear crystals
Torner Sabata, Lluís; Wright, E M
The mutual trapping and locking of intense fundamental and secondharmonic continuouswave light beams propagating in bulk crystals with large secondorder nonlinearities is investigated. We report the outcome of a comprehensive series of numerical experiments to study the dynamics of the excitation of solitons with Gaussian input beams under different material and excitation conditions in terms of input powers, wavevector mismatch, and linear walkoff between the fundamental and the secondharmonic waves. We show the dynamics of the mutual trapping and study how solitons emerge from the input beams in a wide variety of conditions that are not necessarily close to those given by stationary solutions of the governing equations. Solitons also emerge with inputs that fall far from those solutions. We specifically investigate the dynamics of soliton excitation with only the fundamental beam at the input face of the nonlinear crystal and in configurations with a moderately large phase mismatch. We find large oscillations in the amplitude of the beams with potentially important implications. We also study the mutual dragging of the beams in the presence of linear walkoff and in particular of phasematching geometries with a nonsmall, but moderate, walkoff.
20161205T16:52:08Z
Torner Sabata, Lluís
Wright, E M
The mutual trapping and locking of intense fundamental and secondharmonic continuouswave light beams propagating in bulk crystals with large secondorder nonlinearities is investigated. We report the outcome of a comprehensive series of numerical experiments to study the dynamics of the excitation of solitons with Gaussian input beams under different material and excitation conditions in terms of input powers, wavevector mismatch, and linear walkoff between the fundamental and the secondharmonic waves. We show the dynamics of the mutual trapping and study how solitons emerge from the input beams in a wide variety of conditions that are not necessarily close to those given by stationary solutions of the governing equations. Solitons also emerge with inputs that fall far from those solutions. We specifically investigate the dynamics of soliton excitation with only the fundamental beam at the input face of the nonlinear crystal and in configurations with a moderately large phase mismatch. We find large oscillations in the amplitude of the beams with potentially important implications. We also study the mutual dragging of the beams in the presence of linear walkoff and in particular of phasematching geometries with a nonsmall, but moderate, walkoff.