FOTONICA  Grup de Recerca de Fotònica
http://hdl.handle.net/2117/3270
20161203T05:05:04Z

Twodimensional solitons with secondorder nonlinearities
http://hdl.handle.net/2117/97729
Twodimensional solitons with secondorder nonlinearities
Torner Sabata, Lluís; Menyuk, Curtis; Torruellas, William; Stegeman, George
We investigate the propagation of intense Gaussian beams in materials with quadratic nonlinearity. Excitation of (2 + 1) solitons is numerically predicted at finite phase mismatch and in the presence of linear walkoff between the fundamental and secondharmonic waves. The numerical results are interpreted in terms of the conserved quantities of the wave evolution, and the appropriate conditions for the experimental observation of the solitons are discussed.
20161202T17:47:36Z
Torner Sabata, Lluís
Menyuk, Curtis
Torruellas, William
Stegeman, George
We investigate the propagation of intense Gaussian beams in materials with quadratic nonlinearity. Excitation of (2 + 1) solitons is numerically predicted at finite phase mismatch and in the presence of linear walkoff between the fundamental and secondharmonic waves. The numerical results are interpreted in terms of the conserved quantities of the wave evolution, and the appropriate conditions for the experimental observation of the solitons are discussed.

Bright solitons with secondorder nonlinearities
http://hdl.handle.net/2117/97726
Bright solitons with secondorder nonlinearities
Torner Sabata, Lluís; Menyuk, Curtis; Stegeman, George
We investigate the mutual trapping of intense fundamental and secondharmonic waves propagating in materials with secondorder nonlinearity. Consistent with Menyuk’s robustness hypothesis of solitons, we numerically observe that solitonlike waves emerge from the input signal over a wide range of excitation conditions for both signs of the phase mismatch and in the presence of moderate linear walkoff between the interacting waves. The solitons exist above a threshold intensity and in general arise as oscillating states. The trapping of the waves is governed by the sign of the phase mismatch, by the beam or pulse width, and by the absolute value of the phase mismatch through the ratios among the characteristic lengths of the wave evolution, namely, the diffractive, walkoff, and nonlinear interaction lengths.
20161202T17:16:41Z
Torner Sabata, Lluís
Menyuk, Curtis
Stegeman, George
We investigate the mutual trapping of intense fundamental and secondharmonic waves propagating in materials with secondorder nonlinearity. Consistent with Menyuk’s robustness hypothesis of solitons, we numerically observe that solitonlike waves emerge from the input signal over a wide range of excitation conditions for both signs of the phase mismatch and in the presence of moderate linear walkoff between the interacting waves. The solitons exist above a threshold intensity and in general arise as oscillating states. The trapping of the waves is governed by the sign of the phase mismatch, by the beam or pulse width, and by the absolute value of the phase mismatch through the ratios among the characteristic lengths of the wave evolution, namely, the diffractive, walkoff, and nonlinear interaction lengths.

Hybrid waves guided by ultrathin films
http://hdl.handle.net/2117/97718
Hybrid waves guided by ultrathin films
Torner Sabata, Lluís; Pérez Torres, Juan; Ojeda, C.; Mihalache, Dumitru
Abstract:
The existence conditions and waveguiding properties of new hybrid, TEdominant waveguide modes of properly tailored waveguides consisting on ultrathin films cladded by a positive birefringent crystal are analyzed. The results show that the existence conditions of such waves strongly depend on the waveguide parameters. Accordingly, the related guidedtoradiated wave transition holds promise for switching applications requiring a strong sensitive dependence on the material refractive index values.
20161202T15:24:45Z
Torner Sabata, Lluís
Pérez Torres, Juan
Ojeda, C.
Mihalache, Dumitru
Abstract:
The existence conditions and waveguiding properties of new hybrid, TEdominant waveguide modes of properly tailored waveguides consisting on ultrathin films cladded by a positive birefringent crystal are analyzed. The results show that the existence conditions of such waves strongly depend on the waveguide parameters. Accordingly, the related guidedtoradiated wave transition holds promise for switching applications requiring a strong sensitive dependence on the material refractive index values.

Observation of mutual trapping and dragging of twodimensional spatial solitary waves in a quadratic medium
http://hdl.handle.net/2117/97715
Observation of mutual trapping and dragging of twodimensional spatial solitary waves in a quadratic medium
Torruellas, William; Wang, Zou; Torner Sabata, Lluís; Stegeman, George
We report experimental evidence for trapping of twodimensional (2 + 1) spatial solitary waves in a KTP crystal resulting from its secondorder nonlinearity. In addition, dragging of the solitary beams is observed as a function of fundamental input intensity and of the relative phase difference between the fundamental and the second harmonic when beams at both frequencies are coherently launched.
20161202T14:39:46Z
Torruellas, William
Wang, Zou
Torner Sabata, Lluís
Stegeman, George
We report experimental evidence for trapping of twodimensional (2 + 1) spatial solitary waves in a KTP crystal resulting from its secondorder nonlinearity. In addition, dragging of the solitary beams is observed as a function of fundamental input intensity and of the relative phase difference between the fundamental and the second harmonic when beams at both frequencies are coherently launched.

Beam steering by x(2) trapping
http://hdl.handle.net/2117/97713
Beam steering by x(2) trapping
Torner Sabata, Lluís; Torruellas, William; Stegeman, George; Menyuk, Curtis
We show numerically the mutual dragging and locking together of intense fundamental and secondharmonic light beams propagating in secondorder nonlinear media, and we discuss the potential applications of such effects for the steering of beams by spatial phase modulation of the input signals.
20161202T14:25:13Z
Torner Sabata, Lluís
Torruellas, William
Stegeman, George
Menyuk, Curtis
We show numerically the mutual dragging and locking together of intense fundamental and secondharmonic light beams propagating in secondorder nonlinear media, and we discuss the potential applications of such effects for the steering of beams by spatial phase modulation of the input signals.

Interaction of onedimensional bright solitary waves in quadratic media
http://hdl.handle.net/2117/97709
Interaction of onedimensional bright solitary waves in quadratic media
Baboiu, D; Stegeman, G; Torner Sabata, Lluís
© 1995 Optical Society of America. The interaction of spatial solitary waves with one transverse dimension in materials with a ¿(2):¿(2) nonlinearity is investigated. The relation between the phases of the two interacting solitary waves strongly inf luences this interaction and generates threshold phenomena.
20161202T14:06:41Z
Baboiu, D
Stegeman, G
Torner Sabata, Lluís
© 1995 Optical Society of America. The interaction of spatial solitary waves with one transverse dimension in materials with a ¿(2):¿(2) nonlinearity is investigated. The relation between the phases of the two interacting solitary waves strongly inf luences this interaction and generates threshold phenomena.

Stationary trapping of light beams in bulk secondorder nonlinear media
http://hdl.handle.net/2117/97705
Stationary trapping of light beams in bulk secondorder nonlinear media
Torner Sabata, Lluís; Mihalache, Dumitru; Mazilu, D; Wright, E M; Torruellas, W E; Stegeman, G I
The mutual trapping of fundamental and second harmonic, continuouswave light beams propagating in bulk secondorder nonlinear media is studied. We find numerically families of stationary, radially symmetric solitary waves. The transverse profiles of the trapped beams, their scaling properties, and their stability under propagation are investigated as a function of the total power and the linear wavevectormismatch between the waves. We show that at phasematching mutually trapped solitary waves exist for any total wave power, whereas they exist only above a threshold power for both positive and negative phasemismatches.
20161202T13:46:39Z
Torner Sabata, Lluís
Mihalache, Dumitru
Mazilu, D
Wright, E M
Torruellas, W E
Stegeman, G I
The mutual trapping of fundamental and second harmonic, continuouswave light beams propagating in bulk secondorder nonlinear media is studied. We find numerically families of stationary, radially symmetric solitary waves. The transverse profiles of the trapped beams, their scaling properties, and their stability under propagation are investigated as a function of the total power and the linear wavevectormismatch between the waves. We show that at phasematching mutually trapped solitary waves exist for any total wave power, whereas they exist only above a threshold power for both positive and negative phasemismatches.

Diagrammatic analysis of nonlinear planar waveguides
http://hdl.handle.net/2117/97658
Diagrammatic analysis of nonlinear planar waveguides
Pérez Torres, Juan; Torner Sabata, Lluís
We show that universal V–b diagrams provide a powerful tool for analyzing the properties of nonlinear TEpolarized waves guided by optical planar structures. Here we focus on a waveguide consisting of an optically linear film bounded by a saturable nonlinear substrate and cladding. Relevant information on existence conditions and stability of the different allowed nonlinear guided waves is summarized in a few diagrams, and waveguiding properties can be immediately read off them. Critical, powerindependent values of the various waveguide parameters for the different kinds of wave that exist have been identified, and we give the condition in parameter space that ensures stable propagation in a symmetric structure.
20161201T18:42:34Z
Pérez Torres, Juan
Torner Sabata, Lluís
We show that universal V–b diagrams provide a powerful tool for analyzing the properties of nonlinear TEpolarized waves guided by optical planar structures. Here we focus on a waveguide consisting of an optically linear film bounded by a saturable nonlinear substrate and cladding. Relevant information on existence conditions and stability of the different allowed nonlinear guided waves is summarized in a few diagrams, and waveguiding properties can be immediately read off them. Critical, powerindependent values of the various waveguide parameters for the different kinds of wave that exist have been identified, and we give the condition in parameter space that ensures stable propagation in a symmetric structure.

Nonlinear hybrid guided waves in birefringent media
http://hdl.handle.net/2117/97648
Nonlinear hybrid guided waves in birefringent media
Pérez Torres, Juan; Torner Sabata, Lluís; Lederer, F.; Mihalache, Dumitru; Baboiu, Daniel; Ciumac, Mariana
The waveguiding properties of nonlinear hybrid waves guided by integratedoptics structures containing both birefringent crystals and isotropic nonlinear media have been investigated. The existence of both TE and TMdominant stationary hybrid waves guided by an ultrathinfilm configuration has been pointed out, and a thresholding behavior, with a tunable minimum power through the crystal opticalaxis orientation, has been found.
20161201T17:43:15Z
Pérez Torres, Juan
Torner Sabata, Lluís
Lederer, F.
Mihalache, Dumitru
Baboiu, Daniel
Ciumac, Mariana
The waveguiding properties of nonlinear hybrid waves guided by integratedoptics structures containing both birefringent crystals and isotropic nonlinear media have been investigated. The existence of both TE and TMdominant stationary hybrid waves guided by an ultrathinfilm configuration has been pointed out, and a thresholding behavior, with a tunable minimum power through the crystal opticalaxis orientation, has been found.

Bloch oscillations in optical and Zeeman lattices in the presence of spinorbit coupling
http://hdl.handle.net/2117/97646
Bloch oscillations in optical and Zeeman lattices in the presence of spinorbit coupling
Kartashov, Yaroslav V.; Konotop, Vladimir V; Zezyulin, Dmitry A; Torner Sabata, Lluís
We address Bloch oscillations of a spinorbit coupled atom in periodic potentials of two types: optical and Zeeman lattices. We show that in optical lattices the spinorbit coupling allows controlling the direction of atomic motion and may lead to complete suppression of the oscillations at specific values of the coupling strength. In Zeeman lattices the energy bands are found to cross each other at the boundaries of the Brillouin zone, resulting in period doubling of the oscillations. In all cases, the oscillations are accompanied by rotation of the pseudospin, with a dynamics that is determined by the strength of the spinorbit coupling. The predicted effects are discussed also in terms of a WannierStark ladder, which in optical lattices consist of two mutually shifted equidistant subladders.
20161201T17:30:20Z
Kartashov, Yaroslav V.
Konotop, Vladimir V
Zezyulin, Dmitry A
Torner Sabata, Lluís
We address Bloch oscillations of a spinorbit coupled atom in periodic potentials of two types: optical and Zeeman lattices. We show that in optical lattices the spinorbit coupling allows controlling the direction of atomic motion and may lead to complete suppression of the oscillations at specific values of the coupling strength. In Zeeman lattices the energy bands are found to cross each other at the boundaries of the Brillouin zone, resulting in period doubling of the oscillations. In all cases, the oscillations are accompanied by rotation of the pseudospin, with a dynamics that is determined by the strength of the spinorbit coupling. The predicted effects are discussed also in terms of a WannierStark ladder, which in optical lattices consist of two mutually shifted equidistant subladders.