Now showing items 1-20 of 32

    • El 50 aniversari del Làser: fites aconseguides en ciència i tecnologia, i perspectives de futur 

      Vilaseca Alavedra, Ramon (2010-05-07)
      Audiovisual
      Open Access
      Un làser és un dispositiu que utilitza l'emissió estimulada o induïda per generar un feix de llum. Però què ha fet fins ara i quin és el seu futur?
    • Activitats del grup de recerca Dinàmica No lineal, Òptica no lineal i Làsers 

      Vilaseca Alavedra, Ramon (Campus de Terrassa de la UPC, 2013-06-13)
      Conference report
      Open Access
    • Activitats del Grup de Recerca en Dinàmica no lineal, Òptica no lineal i Làsers (DONLL)" 

      Vilaseca Alavedra, Ramon (Campus de Terrassa de la UPC, 2013-06-13)
      Conference report
      Open Access
    • Adiabatic population transfer in the D1 transition of 39K 

      Fernández Soler, Juan José; Font García, Josep Lluís; Vilaseca Alavedra, Ramon (2018-06-22)
      Article
      Open Access
      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 ...
    • All optical implementation of a stochastic logic gate using a VCSEL with external optical injection 

      Perrone, S.; Masoller Alonso, Cristina; Vilaseca Alavedra, Ramon (2011)
      Conference report
      Open Access
      We perform numerical simulations of the dynamics of two VCSELs optically coupled in a master-slave configuration. We show that the interplay of nonlinearity and spontaneous emission noise can yield logic behavior, and the ...
    • Beam focalization by chirped mirrors 

      Cheng, Yu Chieh; Peckus, Martynas; Kicas, Simonas; Trull Silvestre, José Francisco; Cojocaru, Crina; Vilaseca Alavedra, Ramon; Drazdys, Ramutis; Staliunas, Kestutis (Optical Society of American (OSA), 2014)
      Conference report
      Restricted access - confidentiality agreement
      A novel application of chirped dielectric mirrors for narrow beam focalization is proposed and demonstrated numerically and experimentally. Analogy to temporal dispersion compensation by chirped dielectric mirrors is discussed.
    • Broadband third harmonic generation in quadratic media with disordered ferroelectric domains 

      Kalinowski, K.; Roppo, Vito; Wang, W.; Neshev, Dragomir N.; Kong, Y.; Cojocaru, Crina; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Staliunas, Kestutis; Krolikowski, Wieslaw; Kivshar, Yu. (2010)
      Conference report
      Restricted access - publisher's policy
      We study nonlinear frequency generation in media with random ferroelectric domain structure. We show that randomness enables one to realize broadband third harmonic generation via cascading of two second order quasi-phase ...
    • Cavity behavior of second and third harmonic inhomogeneous solutions of Maxwell’s equations 

      Roppo, Vito; Cojocaru, Crina; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Scalora, M. (2010)
      Article
      Restricted access - publisher's policy
      We study second and third harmonic generation of ultrashort pulses in a cavity environment and focus on the role of a phase locking phenomenon that causes the pump to trap and drag the generated harmonic fields. The results ...
    • Comparative analysis of ferroelectric domain statistics via nonlinear diffraction in random nonlinear materials 

      Wang, Bin; Switowski, K; Cojocaru, Crina; Roppo, V; Sheng, Yan; Escalora, M.; Kisielewski, J.; Pawlak, D.; Vilaseca Alavedra, Ramon; Akhouayri, H.; Krolikowski, Wieslaw; Trull Silvestre, José Francisco (2018-01-22)
      Article
      Open Access
      We present an indirect, non-destructive optical method for domain statistic characterization in disordered nonlinear crystals having homogeneous refractive index and spatially random distribution of ferroelectric domains. ...
    • Controlling the likelihood of rogue waves in an optically injected semiconductor laser via direct current modulation 

      Perrone, Sandro; Vilaseca Alavedra, Ramon; Zamora-Munt, Jordi; Masoller Alonso, Cristina (2014-03-06)
      Article
      Open Access
      Extreme and rare events are nowadays the object of intensive research. Rogue waves are extreme waves that appear suddenly in many natural systems, even in apparently calm situations. Here we study numerically the rogue ...
    • Diffraction control of reflected beam by chirped mirror 

      Cheng, Yu Chieh; Peckus, Martynas; Kicas, S.; Trull Silvestre, José Francisco; Cojocaru, Crina; Vilaseca Alavedra, Ramon; Drazdys, R.; Staliunas, Kestutis (2013)
      Conference lecture
      Restricted access - publisher's policy
      We propose and demonstrate a novel functionality of chirped mirror for monochromatic light beams: a diffraction control in reflections resulting in focusing or imaging of beams. The chirped mirrors, commonly used for ...
    • Einstein : física, enginyeria i matemàtiques 

      Vilaseca Alavedra, Ramon (2004-09-15)
      Audiovisual
      Open Access
      "L’any 2005 fou declarat Any Mundial de la Física. Coincideix amb el centenari de publicacions d’Albert Einstein sobre el moviment brownià, sobre els quanta de llum i sobre relativitat especial. Les idees d’Einstein ...
    • Einstein: física, tecnologia i matemàtiques 

      Vilaseca Alavedra, Ramon (2014-01-31)
      Other
      Open Access
      "L’any 2005 fou declarat Any Mundial de la Física. Coincideix amb el centenari de publicacions d’Albert Einstein sobre el moviment brownià, sobre els quanta de llum i sobre relativitat especial. Les idees d’Einstein ...
    • El láser, fuente de fenómenos y dinámicas no lineales 

      Vilaseca Alavedra, Ramon (2010-10-01)
      Article
      Restricted access - publisher's policy
    • ELECTRICITAT I MAGNETISME (Examen 2n Quadr.) 

      Vilaseca Alavedra, Ramon (Universitat Politècnica de Catalunya, 2005-06-06)
      Exam
      Restricted access to the UPC academic community
    • Enhanced efficiency of the second harmonic inhomogeneous component in an opaque cavity 

      Roppo, Vito; Raineri, F.; Raj, R; Sagnes, I.; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Scalora, M.; Cojocaru, Crina (2011-05-15)
      Article
      Open Access
      In this Letter, we experimentally demonstrate the enhancement of the inhomogeneous second harmonic conversion in the opaque region of a GaAs cavity with efficiencies of the order of 0.1% at 612nm, using 3 ps pump pulses ...
    • Flat focusing mirror 

      Cheng, Yu Chieh; Kicas, Simonas; Trull Silvestre, José Francisco; Peckus, Martynas; Cojocaru, Crina; Vilaseca Alavedra, Ramon; Drazdys, Ramutis; Staliunas, Kestutis (MACMILLAN PUBLISHERS LIMITED, 2014-09-17)
      Article
      Open Access
      The control of spatial propagation properties of narrow light beams such as divergence, focusing or imaging are main objectives in optics and photonics. In this letter, we propose and demonstrate experimentally a flat ...
    • Gain/loss periodic spatial modulated materials on a wavelength scale 

      Staliunas, Kestutis; Herrero Simon, Ramon; Vilaseca Alavedra, Ramon (IEEE Press. Institute of Electrical and Electronics Engineers, 2009-06-28)
      Conference report
      Open Access
    • Harmonic generation from metal-oxide and metal-metal boundaries 

      Escalora, M.; Vincenti, M. A.; de Ceglia, Domenico; Akozbek, Neset; Bloemer, M. J.; De Angelis, C.; Haus, J.W.; Vilaseca Alavedra, Ramon; Trull Silvestre, José Francisco; Cojocaru, Crina (American Physical Society (APS), 2018-08-20)
      Article
      Open Access
      We explore the outcomes of detailed microscopic models by calculating second- and third-harmonic generation from thin-film surfaces with discontinuous free-electron densities. These circumstances can occur in structures ...
    • Harmonic generation in the opaque region of GaAs: the role of the surface and magnetic nonlinearities 

      Rodríguez Suñé, Laura; Trull Silvestre, José Francisco; Escalora, M.; Vilaseca Alavedra, Ramon; Cojocaru, Crina (2019-08-29)
      Article
      Open Access
      Phase-locked second and third harmonic generation in the opaque region of a GaAs wafer is experimentally observed and analyzed both in transmission and reflection. These harmonic components, which are generated close to ...