FOTONICA - Grup de Recerca de Fotònica
http://hdl.handle.net/2117/3270
Thu, 19 Jan 2017 21:40:16 GMT2017-01-19T21:40:16ZStable multicolor periodic-wave arrays
http://hdl.handle.net/2117/99730
Stable multicolor periodic-wave arrays
Kartashov, Yaroslav V.; Egorov, A A; Zelenina, A S; Vysloukh, Victor A.; Torner Sabata, Lluís
We study the existence and stability of periodic-wave arrays propagating in uniform quadratic nonlinear media and discover that they become completely stable above a threshold light intensity. To the best of our knowledge, this is the first example in physics of completely stable periodic-wave patterns propagating in conservative uniform media supporting bright solitons.
Thu, 19 Jan 2017 17:52:20 GMThttp://hdl.handle.net/2117/997302017-01-19T17:52:20ZKartashov, Yaroslav V.Egorov, A AZelenina, A SVysloukh, Victor A.Torner Sabata, LluísWe study the existence and stability of periodic-wave arrays propagating in uniform quadratic nonlinear media and discover that they become completely stable above a threshold light intensity. To the best of our knowledge, this is the first example in physics of completely stable periodic-wave patterns propagating in conservative uniform media supporting bright solitons.Observation of self-trapping of light in walk-off compensating tandems
http://hdl.handle.net/2117/99729
Observation of self-trapping of light in walk-off compensating tandems
Carrasco Rodríguez, Sílvia; Petrov, D V; Pérez Torres, Juan; Torner Sabata, Lluís; Kim, H; Stegeman, G I; Zondy, J J
We report the first experimental observation, to our knowledge, of the self-trapping of light in walk-off-compensating optical tandems. The experiment was conducted with picosecond light pulses in a ten-plate optically contacted tandem made of potassium titanyl phosphate prepared for phase matching along a special geometry featuring a huge local walk-off. The observation should open the door to the exploration of multicomponent soliton formation in new classes of materials and settings.
Thu, 19 Jan 2017 17:49:18 GMThttp://hdl.handle.net/2117/997292017-01-19T17:49:18ZCarrasco Rodríguez, SílviaPetrov, D VPérez Torres, JuanTorner Sabata, LluísKim, HStegeman, G IZondy, J JWe report the first experimental observation, to our knowledge, of the self-trapping of light in walk-off-compensating optical tandems. The experiment was conducted with picosecond light pulses in a ten-plate optically contacted tandem made of potassium titanyl phosphate prepared for phase matching along a special geometry featuring a huge local walk-off. The observation should open the door to the exploration of multicomponent soliton formation in new classes of materials and settings.Quasi-phase-matching engineering for spatial control of entangled two-photon states
http://hdl.handle.net/2117/99728
Quasi-phase-matching engineering for spatial control of entangled two-photon states
Pérez Torres, Juan; Alexandescu, A; Carrasco Rodríguez, Sílvia; Torner Sabata, Lluís
We show that transverse engineering of quasi-phase-matched geometries can be used to tailor the spatial mode function that describes the quantum state of photon pairs generated in spontaneous parametric downconversion. We study several geometries and reveal how properly engineered gratings affect, in particular, the spatial correlations embedded in two-photon entangled states.
Thu, 19 Jan 2017 17:44:33 GMThttp://hdl.handle.net/2117/997282017-01-19T17:44:33ZPérez Torres, JuanAlexandescu, ACarrasco Rodríguez, SílviaTorner Sabata, LluísWe show that transverse engineering of quasi-phase-matched geometries can be used to tailor the spatial mode function that describes the quantum state of photon pairs generated in spontaneous parametric downconversion. We study several geometries and reveal how properly engineered gratings affect, in particular, the spatial correlations embedded in two-photon entangled states.Spatial soliton switching in quasi-continuous optical arrays
http://hdl.handle.net/2117/99727
Spatial soliton switching in quasi-continuous optical arrays
Kartashov, Yaroslav V.; Zelenina, A S; Torner Sabata, Lluís; Vysloukh, Victor A.
We report on the phenomenon of trapping and switching of one-dimensional spatial solitons in Kerr-type nonlinear media with transverse periodic modulation of the refractive index. The solitons slowly radiate upon propagation along the periodic structure and are finally trapped in one of its guiding channels. The position of the output channel can be varied by small changes in the launching angle.
Thu, 19 Jan 2017 17:38:10 GMThttp://hdl.handle.net/2117/997272017-01-19T17:38:10ZKartashov, Yaroslav V.Zelenina, A STorner Sabata, LluísVysloukh, Victor A.We report on the phenomenon of trapping and switching of one-dimensional spatial solitons in Kerr-type nonlinear media with transverse periodic modulation of the refractive index. The solitons slowly radiate upon propagation along the periodic structure and are finally trapped in one of its guiding channels. The position of the output channel can be varied by small changes in the launching angle.Eigenvalue control and switching by fission of multisoliton bound states in planar waveguides
http://hdl.handle.net/2117/99726
Eigenvalue control and switching by fission of multisoliton bound states in planar waveguides
Aleshkevich, V A; Kartashov, Yaroslav V.; Zelenina, A S; Vysloukh, Victor A.; Pérez Torres, Juan; Torner Sabata, Lluís
We report the results of numerical studies of the fission of ¿-soliton bound states at the interface formed by a Kerr nonlinear medium and a linear dielectric in a planar waveguide. A variety of effects are shown to occur, with applications to all-optical eigenvalue soliton control.
Thu, 19 Jan 2017 17:35:14 GMThttp://hdl.handle.net/2117/997262017-01-19T17:35:14ZAleshkevich, V AKartashov, Yaroslav V.Zelenina, A SVysloukh, Victor A.Pérez Torres, JuanTorner Sabata, LluísWe report the results of numerical studies of the fission of ¿-soliton bound states at the interface formed by a Kerr nonlinear medium and a linear dielectric in a planar waveguide. A variety of effects are shown to occur, with applications to all-optical eigenvalue soliton control.Multicolor lattice solitons
http://hdl.handle.net/2117/99724
Multicolor lattice solitons
Kartashov, Yaroslav V.; Torner Sabata, Lluís; Vysloukh, Victor A.
We report on the existence of multicolor solitons supported by periodic lattices made from quadratic nonlinear media. Such lattice solitons bridge the gap between continuous solitons in uniform media and discrete solitons in strongly localized systems and exhibit a wealth of new features. We discovered that, in contrast to uniform media, multipeaked lattice solitons are stable. Thus they open new opportunities for all-optical switching based on soliton packets.
Thu, 19 Jan 2017 17:18:44 GMThttp://hdl.handle.net/2117/997242017-01-19T17:18:44ZKartashov, Yaroslav V.Torner Sabata, LluísVysloukh, Victor A.We report on the existence of multicolor solitons supported by periodic lattices made from quadratic nonlinear media. Such lattice solitons bridge the gap between continuous solitons in uniform media and discrete solitons in strongly localized systems and exhibit a wealth of new features. We discovered that, in contrast to uniform media, multipeaked lattice solitons are stable. Thus they open new opportunities for all-optical switching based on soliton packets.Dynamic localization in optical and Zeeman lattices in the presence of spin-orbit coupling
http://hdl.handle.net/2117/99712
Dynamic localization in optical and Zeeman lattices in the presence of spin-orbit coupling
Kartashov, Yaroslav V.; Konotop, Vladimir V; Zezyulin, Dmitry A; Torner Sabata, Lluís
The dynamic localization of a two-level atom in a periodic potential under the action of spin-orbit coupling and a weak harmonically varying linear force is studied. We consider optical and Zeeman potentials that are either in phase or out of phase in two spinor components, respectively. The expectation value for the position of the atom after one oscillation period of the linear force is recovered in authentic resonances or in pseudoresonances. The frequencies of the linear force corresponding to authentic resonances are determined by the band structure of the periodic potential and are affected by the spin-orbit coupling. The width or dispersion of the wave packet in authentic resonances is usually minimal. The frequencies corresponding to pseudoresonances do not depend on the type of potential and on the strength of the spin-orbit coupling, while the evolution of excitations at the corresponding frequencies is usually accompanied by significant dispersion. Pseudoresonances are determined by the initial phase of the linear force and by the quasimomentum of the wave packet. Due to the spinor nature of the system, the motion of the atom is accompanied by periodic, but not harmonic, spin oscillations. Under the action of spin-orbit coupling the oscillations of the wave packet can be nearly completely suppressed in optical lattices. Dynamic localization in Zeeman lattices is characterized by doubling of the resonant oscillation periods due to band crossing at the boundary of the Brillouin zone. We also show that higher harmonics in the Fourier expansion of the energy band lead to effective dispersion, which can be strong enough to prevent dynamic localization of the Bloch wave packet.
Thu, 19 Jan 2017 14:32:45 GMThttp://hdl.handle.net/2117/997122017-01-19T14:32:45ZKartashov, Yaroslav V.Konotop, Vladimir VZezyulin, Dmitry ATorner Sabata, LluísThe dynamic localization of a two-level atom in a periodic potential under the action of spin-orbit coupling and a weak harmonically varying linear force is studied. We consider optical and Zeeman potentials that are either in phase or out of phase in two spinor components, respectively. The expectation value for the position of the atom after one oscillation period of the linear force is recovered in authentic resonances or in pseudoresonances. The frequencies of the linear force corresponding to authentic resonances are determined by the band structure of the periodic potential and are affected by the spin-orbit coupling. The width or dispersion of the wave packet in authentic resonances is usually minimal. The frequencies corresponding to pseudoresonances do not depend on the type of potential and on the strength of the spin-orbit coupling, while the evolution of excitations at the corresponding frequencies is usually accompanied by significant dispersion. Pseudoresonances are determined by the initial phase of the linear force and by the quasimomentum of the wave packet. Due to the spinor nature of the system, the motion of the atom is accompanied by periodic, but not harmonic, spin oscillations. Under the action of spin-orbit coupling the oscillations of the wave packet can be nearly completely suppressed in optical lattices. Dynamic localization in Zeeman lattices is characterized by doubling of the resonant oscillation periods due to band crossing at the boundary of the Brillouin zone. We also show that higher harmonics in the Fourier expansion of the energy band lead to effective dispersion, which can be strong enough to prevent dynamic localization of the Bloch wave packet.Parametric amplification of soliton steering in optical lattices
http://hdl.handle.net/2117/99653
Parametric amplification of soliton steering in optical lattices
Kartashov, Yaroslav V.; Torner Sabata, Lluís; Vysloukh, Victor A.
We report on the effect of parametric amplification of spatial soliton swinging in Kerr-type nonlinear media with longitudinal and transverse periodic modulation of the linear refractive index. The parameter areas are found where the soliton center motion is analogous to the motion of a parametrically driven pendulum. This effect has potential applications for controllable soliton steering.
Wed, 18 Jan 2017 18:03:03 GMThttp://hdl.handle.net/2117/996532017-01-18T18:03:03ZKartashov, Yaroslav V.Torner Sabata, LluísVysloukh, Victor A.We report on the effect of parametric amplification of spatial soliton swinging in Kerr-type nonlinear media with longitudinal and transverse periodic modulation of the linear refractive index. The parameter areas are found where the soliton center motion is analogous to the motion of a parametrically driven pendulum. This effect has potential applications for controllable soliton steering.Soliton trains in photonic lattices
http://hdl.handle.net/2117/99652
Soliton trains in photonic lattices
Kartashov, Yaroslav V.; Vysloukh, Victor A.; Torner Sabata, Lluís
We address the formation and propagation of multi-spot soliton packets in saturable Kerr nonlinear media with an imprinted harmonic transverse modulation of the refractive index. We show that, in sharp contrast to homogeneous media where stable multi-peaked solitons do not exist, the photonic lattices support stable higher-order structures in the form of soliton packets, or soliton trains. Intuitively, such trains can be viewed as made of several lowest order solitons bound together with appropriate relative phases and their existence as stable objects puts forward the concept of compact manipulation of several solitons as a single entity.
Wed, 18 Jan 2017 17:51:04 GMThttp://hdl.handle.net/2117/996522017-01-18T17:51:04ZKartashov, Yaroslav V.Vysloukh, Victor A.Torner Sabata, LluísWe address the formation and propagation of multi-spot soliton packets in saturable Kerr nonlinear media with an imprinted harmonic transverse modulation of the refractive index. We show that, in sharp contrast to homogeneous media where stable multi-peaked solitons do not exist, the photonic lattices support stable higher-order structures in the form of soliton packets, or soliton trains. Intuitively, such trains can be viewed as made of several lowest order solitons bound together with appropriate relative phases and their existence as stable objects puts forward the concept of compact manipulation of several solitons as a single entity.Rotary solitons in Bessel optical lattices
http://hdl.handle.net/2117/99650
Rotary solitons in Bessel optical lattices
Kartashov, Yaroslav V.; Vysloukh, Victor A.; Torner Sabata, Lluís
We introduce solitons supported by Bessel photonic lattices in cubic nonlinear media. We show that the cylindrical geometry of the lattice, with several concentric rings, affords unique soliton properties and dynamics. In particular, in addition to the lowest-order solitons trapped in the center of the lattice, we find soliton families trapped at different lattice rings. Such solitons can be set into controlled rotation inside each ring, thus featuring novel types of in-ring and inter-ring soliton interactions.
Wed, 18 Jan 2017 17:44:31 GMThttp://hdl.handle.net/2117/996502017-01-18T17:44:31ZKartashov, Yaroslav V.Vysloukh, Victor A.Torner Sabata, LluísWe introduce solitons supported by Bessel photonic lattices in cubic nonlinear media. We show that the cylindrical geometry of the lattice, with several concentric rings, affords unique soliton properties and dynamics. In particular, in addition to the lowest-order solitons trapped in the center of the lattice, we find soliton families trapped at different lattice rings. Such solitons can be set into controlled rotation inside each ring, thus featuring novel types of in-ring and inter-ring soliton interactions.