Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 50 of 173 results
  • Experimental and numerical study of the symbolic dynamics of a modulated external-cavity semiconductor laser

     Aragoneses Aguado, Andres; Sorrentino Amaral, Taciano; Perrone, Sandro; Gauthier, Daniel; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    Optics express
    Date of publication: 2014-02-21
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We study the symbolic dynamics of a stochastic excitable optical system with periodic forcing. Specifically, we consider a directly modulated semiconductor laser with optical feedback in the low frequency fluctuations (LFF) regime. We use a method of symbolic time-series analysis that allows us to uncover serial correlations in the sequence of intensity dropouts. By transforming the sequence of inter-dropout intervals into a sequence of symbolic patterns and analyzing the statistics of the patterns, we unveil correlations among several consecutive dropouts and we identify clear changes in the dynamics as the modulation amplitude increases. To confirm the robustness of the observations, the experiments were performed using two lasers under different feedback conditions. Simulations of the Lang-Kobayashi (LK) model, including spontaneous emission noise, are found to be in good agreement with the observations, providing an interpretation of the correlations present in the dropout sequence as due to the interplay of the underlying attractor topology, the external forcing, and the noise that sustains the dropout events.

  • Exploiting nonlinearity and noise in optical tweezers and semiconductor lasers: from resonant damping to stochastic logic gates and extreme pulses.

     Perrone, Sandro
    Defense's date: 2014-02-07
    Department of Applied Physics, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract  Share Reference managers Reference managers Open in new window

    El tema central de esta tesis es el estudio de las dinámicas estocásticas y no lineales en sistemas ópticos. En primer lugar, se ha observado experimentalmente la dinámica estocástica de una partícula colloidal en una trampa óptica sometida a una fuerza externa. Los resultados se han relacionado a los efectos de un ruido paramétrico externo agregado a trampas ópticas monoestables y biestables. Específicamente hemos descubierto un nuevo efecto que hemos nombrado resonancia estocástica amortiguada (SRD), que se refiere a la minimización de la varianza de la posición de la partícula atrapada en un potencial harmonico, en funcion de la intensidad de un ruido paramétrico externo, añadido a la fuerza que actua sobre la particula. Se ha comparado la resonancia estocástica clásica con la amortiguada, y hemos demonstrado que se trata de dos fenómenos que coexisten en el mismo sistema, pero en diferentes regímenes. Además, hemos investigado experimentalmente un sistema monoestable, que exhibe un máximo en el cociente señal-ruido, que no se habia observado anteriormente en una trampa optica. Para estas investigaciones, hemos desarrollado una nueva técnica que aumenta 10 veces el rango de detección del fotodiodo, que explota el crosstalk entre canales.En segundo lugar, hemos estudiado la dinámica estocástica de un láser de semiconductor (SCL) de emision vertical (VCSEL), que presenta biestabilidad en las polarización de la luz emitida y fenomenos de histéresis, al variar la corriente inyectada o al variar la potencia óptica inyectada.Hemos demostrado que estas propiedades se pueden utilizar para realizar operaciones lógicas gracias al efecto del ruido de emisión espontánea. Dos señales de entrada lógicas han sido codificadas en tres niveles de potencia inyectada desde un láser guia (llamado master), y la respuesta lógica del laser injectado (slave) fue decodificada a partir de la polarización de la luz emitida. Se ha logrado una respuesta lógica correcta cuando se ajusta la potencia de la injeccion para favorecer, en dos de los niveles de injeccion, a una de las dos polarizaciones, y para favorecer a la otra polarización, en el tercer nivel de injeccion. Hemos demostrado numéricamente que el operador logico basado en la polarizacion emitida por un VCSEL con injeccion optica permite reproducir la tabla de verdad para los operadores lógicos OR y NOR. La extensión a los operadores logicos AND y NAND es de muy simple implementaciòn. Codificando las señales de entrada en forma optica hemos sido capaces de reducir el tiempo mínimo de bit requerido para realizar operaciones logicas correctamente, desde 30 ns, obtenido previamente mediante codificacion optoelectrónica, hasta 5 ns.El tercer objetivo de esta tesis es el estudio de la dinámica no lineal caótica de un SCL inyectado ópticamente en la region de parametros donde se observan esporadicamente picos extremos de intensidad, llamados Rogue Waves (RWs). Nuestros estudios nos permiten concluir que, agregando ruido moderado de intensidad apropiada, el número de pulsos extremos aumenta respecto al caso determinista. Por el contrario, en algunas regiones de parametros, agregar un ruido de baja intensidad da lugar a una significativa disminución de los pulsos extremos. Con el fin de suprimir o inducir estos pulsos extremos, hemos investigado los efectos de una modulación periódica de la corriente del láser. Hemos observado que esta modulacion puede efectivamente suprimir o inducir RWs, dependiendo de la frecuencia de la modulacion.

  • Access to the full text
    Multidimensional subwavelength position sensing using a semiconductor laser with optical feedback  Open access

     Cohen, Seth; Aragoneses Aguado, Andres; Rontani, Damien; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina; Gauthier, Daniel
    Optics letters
    Date of publication: 2013-11-01
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    We demonstrate experimentally how to harness quasi-periodic dynamics in a semiconductor laser with dual optical feedback for measuring subwavelength changes in each arm of the cavity simultaneously. We exploit the multifrequency spectrum of quasi-periodic dynamics and show that independent frequency shifts are mapped uniquely to two-dimensional displacements of the arms in the external cavity. Considering a laser diode operating at telecommunication wavelength ¿¿1550¿¿nm, we achieve an average nanoscale resolution of approximately 9.8 nm (~¿/160).

    We demonstrate experimentally how to harness quasi-periodic dynamics in a semiconductor laser with dual optical feedback for measuring subwavelength changes in each arm of the cavity simultaneously. We exploit the multifrequency spectrum of quasi-periodic dynamics and show that independent frequency shifts are mapped uniquely to two-dimensional displacements of the arms in the external cavity. Considering a laser diode operating at telecommunication wavelength λ≈1550nm, we achieve an average nanoscale resolution of approximately 9.8 nm (∼λ∕160).

  • Access to the full text
    Distinguishing signatures of determinism and stochasticity in spiking complex systems  Open access

     Aragoneses Aguado, Andres; Rubido, Nicolás; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina
    Scientific reports
    Date of publication: 2013-05-07
    Journal article

    Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

  • Transient and stochastic dynamics in cellular processes  Open access

     Rue Queralt, Pau
    Defense's date: 2013-07-25
    Department of Applied Physics, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    This Thesis studies different cellular and cell population processes driven by non-linear and stochastic dynamics. The problems addressed here gravitate around the concepts of transient dynamics and relaxation from a perturbed to a steady state. In this regard, in all processes studied, stochastic fluctuations, either intrinsically present in or externally applied to these systems play an important and constructive role, by either driving the systems out of equilibrium, interfering with the underlying deterministic laws, or establishing suitable levels of heterogeneity. The first part of the Thesis is committed the analysis of genetically regulated transient cellular processes. Here, we analyse, from a theoretical standpoint, three genetic circuits with pulsed excitable dynamics. We show that all circuits can work in two different excitable regimes, in contrast to what was previously speculated. We also study how, in the presence of molecular noise, these excitable circuits can generate periodic polymodal pulses due to the combination of two noise induced phenomena: stabilisation of an unstable spiral point and coherence resonance. We also studied an excitable genetic mechanism for the regulation of the transcriptional fluctuations observed in some pluripotency factors in Embryonic Stem cells. In the embryo, pluripotency is a transient cellular state and the exit of cells from it seems to be associated with transcriptional fluctuations. In regard to pluripotency control, we also propose a novel mechanism based on the post-translational regulation of a small set of four pluripotency factors. We have validated the theoretical model, based on the formation of binary complexes among these factors, with quantitative experimental data at the single-cell level. The model suggests that the pluripotency state does not depend on the cellular levels of a single factor, but rather on the equilibrium of correlations between the different proteins. In addition, the model is able to anticipate the phenotype of several mutant cell types and suggests that the regulatory function of the protein interactions is to buffer the transcriptional activity of Oc4, a key pluripotency factor. In the second part of the Thesis we studied the behaviour of a computational cell signalling network of the human fibroblast in the presence of external fluctuations and signals. The results obtained here indicate that the network responds in a nontrivial manner to background chatter, both intrinsically and in the presence of external periodic signals. We show that these responses are consequence of the rerouting of the signal to different network information-transmission paths that emerge as noise is modulated. Finally, we also study the cell population dynamics during the formation of microbial biofilms, wrinkled pellicles of bacteria glued by an extracellular matrix that are one of the simplest cases of self-organised multicellular structures. In this Thesis we develop a spatiotemporal model of cellular growth and death that accounts for the experimentally observed patterns of massive bacterial death that precede wrinkle formation in biofilms. These localised patterns focus mechanical forces during biofilm expansion and trigger the formation of the characteristic ridges. In this sense, the proposed model suggests that the death patterns emerge from the mobility changes in bacteria due to the production of extracellular matrix and the spatially inhomogeneous cellular growth. An important prediction of the model is that matrix productions is crucial for the appearance of the patterns and, therefore for winkle formation. We have also experimentally validated validated this prediction with matrix deficient bacterial strains, which show neither death patterns nor wrinkles.

    En aquesta Tesi s’estudien diferents processos intracel·lulars i de poblacions cel·lulars regits per dinàmica estocàstica i no lineal. El problemes biològics tractats graviten al voltant el concepte de dinàmica transitòria i de relaxació d’un estat dinàmic pertorbat a l’estat estacionari. En aquest sentit, en tots els processos estudiats, les fluctuacions estocàstiques, presents intrínsecament o aplicades de forma externa, hi tenen un paper constructiu, ja sigui empenyent els sistemes fora de l’equilibri, interferint amb les lleis deterministes subjacents, o establint els nivells d’heterogeneïtat necessaris. La primera part de la Tesi es dedica a l’estudi de processos cel·lulars transitoris regulats genèticament. En ella analitzem des d’un punt de vista teòric tres circuits genètics de control de polsos excitables i, contràriament al que s’havia especulat anteriorment, establim que tots ells poden treballar en dos tipus de règim excitable. Analitzem també com, en presència de soroll molecular, aquests circuits excitables poden generar polsos periòdics i multimodals degut a la combinació de dos fenòmens induïts per soroll: l’estabilització estocàstica d’estats inestables i la ressonància de coherència. D’altra banda, estudiem com un mecanisme genètic excitable pot ser el responsable de regular a nivell transcripcional les fluctuacions que s’observen experimentalment en alguns factors de pluripotència en cèl·lules mare embrionàries. En l’embrió, la pluripotència és un estat cel·lular transitori i la sortida de les cèl·lules d’aquest sembla que està associada a fluctuacions transcripcionals. En relació al control de la pluripotència, presentem també un nou mecanisme basat en la regulació post-traduccional d’un petit conjunt de 4 factors de pluripotència. El model teòric proposat, basat en la formació de complexos entre els diferents factors de pluripotència, l’hem validat mitjançant experiments quantitatius en cèl·lules individuals. El model postula que l’estat de pluripotència no depèn dels nivells cel·lulars d’un únic factor, sinó d’un equilibri de correlacions entre diverses proteïnes. A més, prediu el fenotip de cèl·lules mutants i suggereix que la funció reguladora de les interaccions entre les quatre proteïnes és la d’esmorteir l’activitat transcripcional d’Oct4, un dels principals factors de pluripotència. En el segon apartat de la Tesi estudiem el comportament d’una xarxa computacional de senyalització cel·lular de fibroblast humà en presència de senyals externs fluctuants i cíclics. Els resultats obtinguts mostren que la xarxa respon de forma no trivial a les fluctuacions ambientals, fins i tot en presència d’una senyal externa. Diferents nivells de soroll permeten modular la resposta de la xarxa, mitjançant la selecció de rutes alternatives de transmissió de la informació. Finalment, estudiem la dinàmica de poblacions cel·lulars durant la formació de biofilms, pel·lícules arrugades d’aglomerats de bacteris que conformen un dels exemples més simples d’estructures multicel·lulars autoorganitzades. En aquesta Tesi presentem un model espai-temporal de creixement i mort cel·lular motivat per l’evidència experimental sobre l’aparició de patrons de mort massiva de bacteris previs a la formació de les arrugues dels biofilms. Aquests patrons localitzats concentren les forces mecàniques durant l’expansió del biofilm i inicien la formació de les arrugues característiques. En aquest sentit, el model proposat explica com es formen els patrons de mort a partir dels canvis de mobilitat dels bacteris deguts a la producció de matriu extracel·lular combinats amb un creixement espacialment heterogeni. Una important predicció del model és que la producció de matriu és un procés clau per a l’aparició dels patrons i, per tant de les arrugues. En aquest aspecte, els nostres resultats experimentals en bacteris mutants que no produeixen components essencials de la matriu, confirmen les prediccions.

  • ESTOCASTICIDAD EN SISTEMAS COMPLEJOS NOLINEALES

     Pons Rivero, Antonio Javier; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina; Pigolotti, Simone; Ramirez de La Piscina Millan, Laureano; Peñaranda Ayllon, Angelina; Malagarriga Guasch, Daniel; Dies Miracle, Marta; Aragoneses Aguado, Andres; Deza, Juan Ignacio; Garcia Ojalvo, Jorge
    Participation in a competitive project

     Share

  • Zero-lag synchronization and bubbling in delay-coupled lasers

     Tiana Alsina, Jordi; Hicke, K.; Porte, X.; Soriano, M.C.; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2012-02-21
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Interspike-interval correlations induced by two-state switching in an excitable system

     Schwalger, T.; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Lindner, B.
    Europhysics letters
    Date of publication: 2012-07
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • NEURAL ENGINEERING TRANSFORMATIVE TECHNOLOGIES

     Pons Rivero, Antonio Javier; Torrent Serra, Maria Del Carmen; Masoller Alonso, Cristina; Garcia Ojalvo, Jorge
    Participation in a competitive project

     Share

  • Dynamical and synchronization properties of delay-coupled lasers

     Martinez Gonzalez, Maria Cristina; Soriano, M. C.; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Fischer, Ingho
    Date of publication: 2011
    Book chapter

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • STOCHASTICITY,COMPLEXITY AND SYNCHRONIZATION IN SEMICONDUCTOR LASERS  Open access

     Tiana Alsina, Jordi
    Defense's date: 2011-11-10
    Department of Applied Physics, Universitat Politècnica de Catalunya
    Theses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The purpose of this Thesis is study the dynamical behavior of semiconductor lasers with optical feedback, as well as analyze the synchronization of this kind of systems under different coupling arquitectures. This study has been done from an experimental point of view, but in some cases we have used numerical models in order to verify and/or extend the experimental results. A semiconductor laser in absence of any optical feedback emits light at constant power. If one wants to induce dynamics in the laser, a good strategy is to introduce an external cavity able to reflect the emitted light back into the laser. Due to this feedback, the laser can show a large variety of dynamical behaviors. In this Thesis we will focus mainly in a dynamical regime known as low frequency fluctuations regime (LFF). The LFF regime takes place when the pump current of the laser is close to its threshold current and the feedback strength is sufficiently large, and it consists in sudden intensity dropouts arising at irregular times, followed by a gradual and stepwise recovery. During this Thesis, we have characterized in detail the dynamical behavior of the time between intensity dropouts for a semiconductor laser with feedback, by using different statistical techniques based on information theory concepts. We have quantified the probability of appearance of certain patterns within the temporal series, as well as its degree of complexity. As a result of these studies, we can conclude that the dynamics of a semiconductor laser with optical feedback is stochastic for pump current values close to the laser threshold. On the other hand, for larger pump currents the dynamics is basically deterministic (chaotic). Numerical simulations have shown a good qualitative and quantitive agreement with the experimental results. During this Thesis we have also studied the ability of semiconductor lasers to synchronize under different coupling architectures. First, we have characterized the leader-laggard dynamics showed by two semiconductor lasers bidirectionally coupled operating at the LFF regime, with a method that takes into account the number of forbidden patterns that appears in the temporal series. We have quantified the degree of stochasticity of the system as a function of the pump current of both lasers. A second coupling architecture studied here, consists in two lasers unidirectionally coupled via two paths. In this case, we have analyzed how the synchronization is affected under different values of the coupling strength of both paths, as well as the potential of this system (or rather, the lack thereof) to be used in chaotic communications. Finally we have characterized the synchronization at zero lag for two lasers coupled bidirectionally via a passive relay. In particular, we have studied the desynchronization events and their statistics for different pump currents. The experimental results obtained in this Thesis give a global perspective of the dynamical statistical properties of semiconductor laser dynamics, both isolated or coupled to other lasers, which contributes to a better understanding of this kind of dynamical systems.

    L’objectiu d’aquesta Tesi ´es l’estudi de la din`amica de l`asers de semiconductor amb retroalimentaci´o `optica, aix´ý com l’an`alisis de la sincronitzaci´o d’aquest tipus de sistemes sota diferents arquitectures d’acoblament. Aquest estudi s’ha fet sempre des d’un punt de vista b`asicament experimental, tot i que en alguns casos hem utilitzat models num`erics per tal de verificar i/o ampliar els resultats experimentals. Un l`aser de semiconductor en abs`encia de retroalimentaci´o `optica o altres perturbacions externes, emet llum a una intensitat pr`acticament constant. Aix´ý doncs, si el que es vol ´es indu¨ýr din`amica en el l`aser, una bona estrat`egia ´es introdu¨ýr una cavitat externa capa¸c de reflexar la llum cap al l`aser. Un cop la llum ´es reinjectada, els l`asers de semiconductor poden mostrar una gran varietat de comportaments din`amics. En aquesta tesis ens centrarem principalment en un r`egim din`amic anomenat r`egim de fluctuacions de baixa frequ`encia (LFF en les seves sigles en angl`es). El r`egim d’LFF es d´ona quan el corrent d’injecci´o del l`aser es troba a prop del seu corrent llindar i la intensitat de la retroalimentaci´o ´es suficientment gran, i est`a caracteritzat per sobtades caigudes de la intensitat a temps irregulars, seguides per una recuperaci´o gradual i escalonada. Durant aquesta Tesi, hem caracteritzat de forma detallada el comportament din`amic de la distribuci´o dels temps entre les caigudes d’intensitat d’un l`aser de semiconductor amb retroalimentaci´o `optica, utilitzant diferents m`etodes estad´ýstics basats en conceptes de teoria de la informaci´o. En particular, hem quantificat la probabilitat d’aparici´o de certs patrons dins les s`eries temporals, aix´ý com el grau de complexitat d’aquestes. Durant aquest estudi hem observat que la din`amica d’un l`aser de semiconductor amb retroalimentaci´o es estoc`astica per valors del corrent d’injecci´o propers al corrent llindar del l`aser. D’altra banda, per a valors m´es grans del corrent d’injecci´o la din`amica ´es m´es determinista (ca`otica). Les simulacions num`eriques realitzades han mostrat un acord qualitatiu i quantitatiu amb els resultats experimentals. Durant aquesta Tesi tamb´e hem estudiat la sincronitzaci´o entre l`asers de semiconductor. Hem analitzat diferents arquitectures d’acoblament. Primer hem caracteritzat la din`amica leader-laggard que presenten dos l`asers de semiconductor acoblats bidireccionalment operant en r`egim de LFFs, amb un m`etode que t´e en compte el nombre de patrons prohibits que apareixen en la s`erie temporal. Hem quantificat el grau d’estocasticitat del sistema en funci´o del nivell de bombeig al qual est`an sotmesos els dos l`asers. La seg¨uent arquitectura d’acoblament que hem estudiat consisteix en dos l`asers acoblats unidireccionalment a trav´es de dos camins. En aquest cas hem analitzat com es veu afectada la sincronitzaci´o sota diferents valors de l’acoblament dels dos camins, aix´ý com el potencial d’aquest esquema experimental per realitzar comunicacions ca`otiques. Per ´ultim hem caracteritzat la sincronitzaci´o a retard zero per dos l`asers acoblats bidireccionalment, a on els dos l`asers tenen la seva pr`opia realimentaci´o `optica. En particular, hem estudiat els events de desincronitzaci´o i la seva estad´ýstica per a diferents corrents d’injecci´o. Els resultats experimentals obtinguts en aquesta Tesi, ofereixen una prespectiva global de les propietats estad´ýstiques de la din`amica de l`asers de semiconductor, tant a¨ýllats com acoblats a altres l`asers, que contribueixen a entendre millor aquests sistemes din`amics.

  • Nonlinear and Stochastic Dynamics of Semiconductor Lasers: Modulation, Transient Dynamics and Synchronization

     Zamora Munt, Jordi
    Defense's date: 2011-06-21
    Department of Physics and Nuclear Engineering, Universitat Politècnica de Catalunya
    Theses

     Share Reference managers Reference managers Open in new window

  • Research activities of the group on nonlinear dynamics, nonlinear optics and lasers (DONLL) at the universitat politècnica de catalunya (Campus de Terrassa)

     Tiana Alsina, Jordi; Zamora Munt, Jordi; Nistor, Ioan Cristian; Roppo, Vito; Maigyte, Lina; Aragoneses Aguado, Andres; Khumar, N.P.; Martinez Gonzalez, Maria Cristina; Fernandez Soler, Juanjo; Serrat Jurado, Carles; Font Garcia, Josep Lluís; Herrero Simon, Ramon; Cojocaru, Crina Maria; Trull, Jose; Masoller Alonso, Cristina; Staliunas, Kestutis; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Vilaseca Alavedra, Ramon
    Óptica pura y aplicada
    Date of publication: 2011-06
    Journal article

     Share Reference managers Reference managers Open in new window

  • Language organization and temporal correlations in the spiking activity of an excitable laser: experiments and model comparison

     Rubido, Nicolás; Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge; Masoller Alonso, Cristina
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2011-08-09
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Quantifying the statistical complexity of low-frequency fluctuations in semiconductor lasers with optical feedback

     Tiana Alsina, Jordi; Torrent Serra, Maria Del Carmen; Rosso, Osvaldo A.; Masoller Alonso, Cristina; Garcia Ojalvo, Jorge
    Physical review A
    Date of publication: 2010
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Quantifying stochasticity in the dynamics of delay-coupled semiconductor lasers via forbidden patterns

     Tiana Alsina, Jordi; Buldu, Jm; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Philosophical transactions of the Royal Society A. Mathematical physical and engineering sciences
    Date of publication: 2010-01
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • DINAMICA NOLINEAL Y ESTOCASTICA EN SISTEMAS FISICOS Y BIOFISICOS

     Zamora Munt, Jordi; Masoller Alonso, Cristina; Domedel Puig, Nuria; Torrent Serra, Maria Del Carmen; Espinar Calvo, Maria Lorena; De Sancristobal Alonso, Belen; Pons Rivero, Antonio Javier; Tiana Alsina, Jordi; Rue Queralt, Pau; Dies Miracle, Marta; Garcia Ojalvo, Jorge
    Participation in a competitive project

     Share

  • Dynamical behavior of delay-coupled semiconductor lasers.

     Martinez Gonzalez, Maria Cristina
    Defense's date: 2009-01-30
    Department of Applied Physics, Universitat Politècnica de Catalunya
    Theses

     Share Reference managers Reference managers Open in new window

  • Access to the full text
    Lag alternance in unidirectional coupled semiconductor lasers  Open access

     Tiana Alsina, Jordi; García López, J.H.; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Conference on lasers and electro-optics
    Presentation's date: 2009-06-14
    Presentation of work at congresses

    Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

  • PROPIETATS DINÀMIQUES I NO LINIALS DE MATERIALS I SITEMES FOTÒNICS, ELÈCTRICS I BIOLÒGICS

     Belana Punseti, Juan; Nistor, Ioan Cristian; Masoller Alonso, Cristina; Domedel Puig, Nuria; Diego Vives, Jose Antonio; Cañadas Lorenzo, Juan Carlos; Mudarra Lopez, Miguel; Òrrit Prat, Jordi; Aragoneses Aguado, Andres; Trull, Jose; Staliunas, Kestutis; Herrero Simon, Ramon; Torrent Serra, Maria Del Carmen; Vilaseca Alavedra, Ramon; Font Garcia, Josep Lluís; Cojocaru, Crina Maria; Espinar Calvo, Maria Lorena; De Sancristobal Alonso, Belen; Pons Rivero, Antonio Javier; Sellarès González, Jordi; Tiana Alsina, Jordi; Zamora Munt, Jordi; Roppo, Vito; Garcia Ojalvo, Jorge
    Participation in a competitive project

     Share

  • Dynamics of globally delay-coupled neurons displaying subthreshold oscillations

     Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Philosophical transactions of the Royal Society A. Mathematical physical and engineering sciences
    Date of publication: 2009-08
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    We study an ensemble of neurons that are coupled through their time-delayed collective mean field. The individual neuron is modelled using a Hodgkin–Huxley-type conductance model with parameters chosen such that the uncoupled neuron displays autonomous subthreshold oscillations of the membrane potential. We find that the ensemble generates a rich variety of oscillatory activities that are mainly controlled by two time scales: the natural period of oscillation at the single neuron level and the delay time of the global coupling. When the neuronal oscillations are synchronized, they can be either in-phase or out-of-phase. The phase-shifted activity is interpreted as the result of a phase-flip bifurcation, also occurring in a set of globally delay-coupled limit cycle oscillators. At the bifurcation point, there is a transition from in-phase to out-of-phase (or vice versa) synchronized oscillations, which is accompanied by an abrupt change in the common oscillation frequency. This phase-flip bifurcation was recently investigated in two mutually delay-coupled oscillators and can play a role in the mechanisms by which the neurons switch among different firing patterns.

  • Interplay of subthreshold activity, time-delayed feedback, and noise on neuronal firing patterns

     Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2008-10
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Controlling the leader-laggard dynamics in delay-synchronized lasers

     Gonzalez, C; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Chaos
    Date of publication: 2007-09
    Journal article

     Share Reference managers Reference managers Open in new window

  • Synchronization via clustering in a small delay-coupled laser network

     Gonzalez, C; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Europhysics letters
    Date of publication: 2007-09
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Synchronization in Semiconductor Laser Rings

     Martin Buldu, Javier; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Journal of lightwave technology
    Date of publication: 2007-06
    Journal article

     Share Reference managers Reference managers Open in new window

  • Processing distributed inputs in coupled excitable lasers

     Martinez Gonzalez, Maria Cristina; Martin Buldu, Javier; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review A
    Date of publication: 2007-11
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Neuronal multistability induced by delay

     Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    International conference on artificial neural networks
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Controlling the leader-laggard dynamics in delay-synchronized lasers

     Martinez Gonzalez, Maria Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Chaos
    Date of publication: 2007
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Synchronization via clustering in a small delay-coupled laser network

     Martinez Gonzalez, Maria Cristina; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Europhysics letters
    Date of publication: 2007-09
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • GABA: Global Approach to Brain Activity (FP6-2005-NEST-Path-043309)

     Garcia Ojalvo, Jorge; Masoller Alonso, Cristina; Torrent Serra, Maria Del Carmen; Pons Rivero, Antonio Javier
    Participation in a competitive project

     Share

  • Ghost stochastic resonance with distributed inputs in pulse-coupled electronic neurons

     Lopera, A; Martin Buldu, Javier; Torrent Serra, Maria Del Carmen; Chialvo, D R; Garcia Ojalvo, Jorge
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2006-02
    Journal article

     Share Reference managers Reference managers Open in new window

  • Episodic synchronization via dynamic injection

     Martin Buldu, Javier; Heil, T; Fischer, I; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review letters
    Date of publication: 2006-01
    Journal article

     Share Reference managers Reference managers Open in new window

  • Zero-lag long-range synchronization via dynamical relaying

     Fischer, I; Vicente, R; Martin Buldu, Javier; Peil, M; Mirasso, C; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Physical review letters
    Date of publication: 2006-09
    Journal article

     Share Reference managers Reference managers Open in new window

  • Dinámica y sincronización de láseres de semiconductor y aplicaciones (TEC2005-07799-C02-02)

     Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen
    Participation in a competitive project

     Share

  • Demultiplexing chaos from multimode semiconductor lasers

     Martin Buldu, Javier; Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen
    IEEE journal of quantum electronics
    Date of publication: 2005-02
    Journal article

     Share Reference managers Reference managers Open in new window

  • Coupling-mediated ghost resonance in mutually injected lasers

     Martin Buldu, Javier; González, C M; Trull, Jose; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Chaos
    Date of publication: 2005-03
    Journal article

     Share Reference managers Reference managers Open in new window

  • Coupling-mediated ghost resonance in mutually injected lasers

     Martin Buldu, Javier; Martinez Gonzalez, Maria Cristina; Trull, Jose; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Chaos
    Date of publication: 2005-03
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Noise and coupling in diode lasers

     Garcia Ojalvo, Jorge; Buldú, J M; González, C M; Torrent Serra, Maria Del Carmen
    5th EUROMECH Nonlinear Dynamics Conference
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Grup Consolidat: Làsers i Propietats Elèctriques i Optiques dels Materials

     Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen; Vilaseca Alavedra, Ramon
    Participation in a competitive project

     Share

  • Dinàmiques no lineals d'autoorganització espai-temporal (2004XT-00013)

     Garcia Ojalvo, Jorge; Auguet Sangra, Carlota Eugenia; Mercader Calvo, Maria Isabel; Ramirez de La Piscina Millan, Laureano; Torrent Serra, Maria Del Carmen; Alonso Maleta, Maria Aranzazu
    Participation in a competitive project

     Share

  • Delay-induced resonances in an optical system with feedback

     Martin Buldu, Javier; Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen
    Physical review E: statistical, nonlinear, and soft matter physics
    Date of publication: 2004-04
    Journal article

     Share Reference managers Reference managers Open in new window

  • Two-photon cavity solitons in a laser: radiative profiles, interaction and control

     Serrat Jurado, Carles; Torrent Serra, Maria Del Carmen; Vilaseca Alavedra, Ramon; Garcia Ojalvo, Jorge; Brambilla, M
    Journal of optics B. Quantum and semiclasical optics
    Date of publication: 2004-05
    Journal article

     Share Reference managers Reference managers Open in new window

  • Multimode synchronization and communication using unidirectionally coupled semiconductor lasers

     Martin Buldu, Javier; Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen
    IEEE journal of quantum electronics
    Date of publication: 2004-06
    Journal article

     Share Reference managers Reference managers Open in new window

  • External noise in semiconductor lasers

     Martin Buldu, Javier; Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen; Sancho, J M; Mirasso, C R; Chialvo, D R
    Proceedings of SPIE, the International Society for Optical Engineering
    Date of publication: 2004-05
    Journal article

     Share Reference managers Reference managers Open in new window

  • Ghost resonance in coupled lasers

     Martin Buldu, Javier; Gonzalez, C M; Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen; Trull, Jose; Mirasso, Claudio; Chialvo, Dante R.
    AIP Conference proceedings
    Date of publication: 2004-12
    Journal article

     Share Reference managers Reference managers Open in new window

  • Autoorganización en sistemas complejos bajo fuctuaciones

     Garcia Ojalvo, Jorge; Torrent Serra, Maria Del Carmen
    Participation in a competitive project

     Share

  • Ghost resonance in coupled lasers

     Garcia Ojalvo, Jorge; Buldú, J M; González, C M; Torrent Serra, Maria Del Carmen; Trull, Jose; Mirasso, C R
    Experimental Chaos Conference 8 (ECC8)
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window

  • Enlargement of the inversionless lasing domain by using broad-area cavities

     Mompart, J; Torrent Serra, Maria Del Carmen; Ahufinger, V; Garcia Ojalvo, Jorge; Corbalán, R; Vilaseca Alavedra, Ramon
    Journal of optics B. Quantum and semiclasical optics
    Date of publication: 2003-06
    Journal article

     Share Reference managers Reference managers Open in new window

  • Cavity solitons in two-level lasers with dense amplifying medium

     Ahufinger, V; Garcia Ojalvo, Jorge; Mompart, J; Torrent Serra, Maria Del Carmen; Corbalán, R; Vilaseca Alavedra, Ramon
    Physical review letters
    Date of publication: 2003-08
    Journal article

     Share Reference managers Reference managers Open in new window

  • Ghost resonance in a semiconductor laser with optical feedback

     Martin Buldu, Javier; Chialvo, D R; Mirasso, C R; Torrent Serra, Maria Del Carmen; Garcia Ojalvo, Jorge
    Europhysics letters
    Date of publication: 2003-10
    Journal article

     Share Reference managers Reference managers Open in new window