Enviaments recents

  • Differentiating resting brain states using ordinal symbolic analysis 

    Quintero Quiroz, Carlos Alberto; Montesano Del Campo, Luis; Pons Rivero, Antonio Javier; Torrent Serra, Maria del Carmen; García Ojalvo, Jordi; Masoller Alonso, Cristina (Institute of Physics (IOP), 2018-10-08)
    Article
    Accés restringit per política de l'editorial
    Symbolic methods of analysis are valuable tools for investigating complex time-dependent signals. In particular, the ordinal method defines sequences of symbols according to the ordering in which values appear in a time ...
  • Stabilization of broad-area semiconductor laser sources by simultaneous index and pump modulations 

    Waseem Ahmed, Waqas; Kumar, Shubham; Medina Pardell, Judith; Botey Cumella, Muriel; Herrero Simon, Ramon; Staliunas, Kestutis (2018-06-01)
    Article
    Accés restringit per política de l'editorial
    We show that the emission of broad-area semiconductor amplifiers and lasers can be efficiently stabilized by introducing two-dimensional periodic modulations simultaneously on both the refractive index and the pump (gain–loss) ...
  • Invisibility on demand based on a generalized Hilbert transform 

    Hayran, Zeki; Herrero Simon, Ramon; Botey Cumella, Muriel; Kurt, Hamza; Staliunas, Kestutis (American Physical Society (APS), 2018-07-12)
    Article
    Accés obert
    We propose a feasible invisibility approach to suppress the scattering of waves from or to given directions and for particular frequencies, i.e., invisibility on demand. We derive a generalized Hilbert transform for a ...
  • Non-perturbative generation of DUV/VUV harmonics from crystal surfaces at 108 MHz repetition rate 

    Seres, Jozsef; Seres, Enikoe; Serrat Jurado, Carles; Schumm, Thorsten (2018-08-08)
    Article
    Accés obert
    We demonstrate non-perturbative 3rd (267 nm) and 5th (160 nm) harmonic generation in solids from a Ti:sapphire frequency comb (800 nm) at 108 MHz repetition rate. The experiments show that non-perturbative low harmonics ...
  • Adiabatic population transfer in the D1 transition of 39K 

    Fernández Soler, Juan José; Font Garcia, Josep Lluís; Vilaseca Alavedra, Ramon (2018-06-22)
    Article
    Accés obert
    Four-photon stimulated Raman adiabatic passage–like (STIRAP-like) processes in the frame of the D1 optical transition line of atomic 39K are investigated theoretically by means of a rigorous model that takes into account ...
  • State space reconstruction of spatially extended systems and of time delayed systems from the time series of a scalar variable 

    Quintero Quiroz, Carlos Alberto; Torrent Serra, Maria del Carmen; Masoller Alonso, Cristina (Institute of Physics (IOP), 2018-07-11)
    Article
    Accés obert
    The space-time representation of high-dimensional dynamical systems that have a well defined characteristic time scale has proven to be very useful to deepen the understanding of such systems and to uncover hidden features ...
  • Reevaluation of radiation reaction and consequences for light-matter interactions at the nanoscale 

    Escalora, M.; Vinceti, Maria Antonietta; Ceglia, Domenico de; Trull Silvestre, José Francisco; Cojocaru, Crina (2018-06-27)
    Article
    Accés obert
    In the context of electromagnetism and nonlinear optical interactions, damping is generally introduced as a phenomenological, viscous term that dissipates energy, proportional to the temporal derivative of the polarization. ...
  • Sharp acoustic vortex focusing by Fresnel-spiral zone plates 

    Jimenez, Noe; Romero García, Vicenç; Garcia Raffi, Luis Miguel; Staliunas, Kestutis (2018-05-14)
    Article
    Accés restringit per política de l'editorial
    We report the optimal focusing of acoustic vortex beams by using flat lenses based on a Fresnel- spiral diffraction grating. The flat lenses are designed by spiral-shaped Fresnel zone plates composed of one or several arms. ...
  • Self-induced Faraday instability laser 

    Perego, A.M.; Smirnov, Sergey V.; Staliunas, Kestutis; Churkin, D.V.; Wabnitz, Stefan (American Institute of Physics (AIP), 2018-05-22)
    Article
    Accés obert
    We predict the onset of self-induced parametric or Faraday instabilities in a laser, spontaneously caused by the presence of pump depletion, which leads to a periodic gain landscape for light propagating in the cavity. As ...
  • Sub-threshold signal encoding in coupled FitzHugh-Nagumo neurons 

    Masoliver Vila, Maria; Masoller Alonso, Cristina (Nature, 2018-05-29)
    Article
    Accés obert
    Despite intensive research, the mechanisms underlying the neural code remain poorly understood. Recent work has focused on the response of a single neuron to a weak, sub-threshold periodic signal. By simulating the stochastic ...
  • Experimental study of modulation waveforms for entraining the spikes emitted by a semiconductor laser with optical feedback 

    Tiana Alsina, Jordi; Quintero Quiroz, Carlos Alberto; Panozzo, M.; Torrent Serra, Maria del Carmen; Masoller Alonso, Cristina (2018-04-02)
    Article
    Accés obert
    The entrainment phenomenon, by which an oscillator adjusts its natural rhythm to an external periodic signal, has been observed in many natural systems. Recently, attention has focused on which are the optimal conditions ...
  • A two dimensional KTiOPO4 photonic crystal grown using a macroporous silicon template 

    Peña Revellez, Alexandra; Finizio, Sergio Di; Todorov Trifonov, Trifon; Carvajal, Joan Josep; Aguiló Díaz, Magdalena; Pallarès Marzal, Josep; Rodríguez Martínez, Ángel; Alcubilla González, Ramón; Marsal Garví, Lluís Francesc; Diaz, Francesc; Martorell Pena, Jordi (2006-09)
    Article
    Accés restringit per política de l'editorial
    2D KTiOPO4 photonic crystals are fabricated using a silicon membrane of air holes as a template. Columns of KTiOPO4 are grown by liquid-phase epitaxy from a substrate into such air holes. The crystallographic orientation ...

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