Ara es mostren els items 21-38 de 38

    • Flat focusing mirrors 

      Staliunas, Kestutis; Cheng, Yu-Chiech; Kicas, Simonas; Trull Silvestre, José Francisco; Cojocaru, Crina; Peckus, Martynas; Vilaseca Alavedra, Ramon; Drazdys, Ramutis (Institute of Electrical and Electronics Engineers (IEEE), 2015)
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      We present the flat focusing mirror - the dielectric mirrors capable to focus and image the narrow beams in reflections. The mirrors are flat, and transversally invariant, i.e. have no optical axis. We consider two different ...
    • 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)
      Text en actes de congrés
      Accés obert
    • 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
      Accés obert
      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
      Accés obert
      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 ...
    • Large nonlinear efficiency enhancement in the visible and UV range from plasmonic gold nanogratings 

      Cojocaru, Crina; Mukhopadhyay, Shroddha; Rodríguez Suñé, Laura; Vicenti, Maria Antonietta; Vilaseca Alavedra, Ramon; Scalora, Michael; Trull Silvestre, José Francisco (Institute of Electrical and Electronics Engineers (IEEE), 2023)
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      We report a combined experimental/theoretical investigation on second and third harmonic generation from a plasmonic gold nanograting, that exhibits a plasmonic resonance in the near IR. The intense field localization leads ...
    • Observation of azimuthal modulation instability and formation of patterns of optical solitons in a quadratic nonlinear crystal 

      Petrov, Dimitri; Torner Sabata, Lluís; Martorell Pena, Jordi; Vilaseca Alavedra, Ramon; Pérez Torres, Juan; Cojocaru, Crina (1998-09)
      Article
      Accés restringit per política de l'editorial
      We report what is believed to be the first experimental demonstration of the azimuthal self-breaking of intense beams containing a vortex phase dislocation into sets of optical spatial solitons in a quadratic nonlinear ...
    • Phase locked second harmonic etalon localization 

      Roppo, Vito; D'Aguanno, G.; Cojocaru, Crina; Raineri, F.; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Raj, R; Scalora, M. (2009)
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      During the last decades a phase locking phenomenon has been observed for second harmonic (SH) generation but only recently it was recognized as such in systematic studies. The general solution of the SHG from a linear/nonlinear ...
    • Pràctiques de l'assignatura 

      Botey Cumella, Muriel; Martorell Pena, Jordi; Belana Punseti, Juan; Carloa Cañadas, Joan; Diego Vives, José Antonio; Font García, Josep Lluís; Martin, Josep; Mudarra López, Miguel; Vilaseca Alavedra, Ramon; Calaf Zayas, Jaume; García Ojalvo, Jordi (Universitat Politècnica de Catalunya, 2000)
      Pràctica
      Accés obert
    • Quantum mechanics 

      Vilaseca Alavedra, Ramon; Acín dal Maschio, Antonio (2009-10-21)
      Audiovisual
      Accés obert
    • Rogue waves in injected semiconductor lasers with current modulation: role of the modulation phase 

      Ahuja, Jatin; Nalawade, Dhananjay Bhiku; Zamora Munt, Jordi; Vilaseca Alavedra, Ramon; Masoller Alonso, Cristina (2014-11-17)
      Article
      Accés restringit per política de l'editorial
      Semiconductor lasers with continuous-wave optical injection display a rich variety of behaviors, including stable locking, periodic or chaotic oscillations, excitable pulses, etc. Within the chaotic regime it has been shown ...
    • Second and third harmonic generation in disordered quadratic nonlinear media: application to short-pulse characterization 

      Roppo, Vito; Wang, W.; Kalinowski, K.; Vilaseca Alavedra, Ramon; Trull Silvestre, José Francisco; Cojocaru, Crina; Staliunas, Kestutis; Krolikowski, Wieslaw; Kivshar, Yu. (2010)
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      We study parametric frequency conversion in quadratic nonlinear media with disordered ferroelectric domains. We demonstrate that disorder allows realizing broadband second- and third-harmonic generation via cascading of ...
    • Second-harmonic generation in disordered quadratic media: role of a ferroelectric domain structure 

      Roppo, Vito; Kalinowski, K.; Wang, W.; Cojocaru, Crina; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Scalora, M.; Krolikowski, Wieslaw; Kivshar, Yu. (2010)
      Text en actes de congrés
      Accés obert
      We study theoretically the second harmonic generation in a nonlinear quadratic crystal with random distribution of ferroelectric domains. We show that the specific features of disordered domain structure greatly affect the ...
    • Second-harmonic generation in disordered quadratic media: role of a ferroelectric domain structure 

      Roppo, Vito; Kalinowski, K.; Wang, W.; Cojocaru, Crina; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Scalora, M.; Krolikowski, Wieslaw; Kivshar, Yu. (2010)
      Text en actes de congrés
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      Naturally grown ferroelectric crystals such as Strontium Barium Niobate (SBN) often exhibit an irregular multidomain structure with rod-like domains [1]. These disordered nonlinear quadratic crystals have attracted a ...
    • Subdiffraction and spatial filtering due to periodic spatial modulation of the gain/loss profile 

      Staliunas, Kestutis; Herrero Simon, Ramon; Vilaseca Alavedra, Ramon (2018-11)
      Report de recerca
      Accés obert
      We investigate light propagation through materials with periodically modulated gain/loss profile in both transverse and longitudinal directions, i.e. in material with two-dimensional modulation in space. We predict effects ...
    • The effect of domain distribution on second harmonic generation in disordered nonlinear media 

      Roppo, Vito; Saltiel, Salomon M.; Wang, W.; Kalinowski, K.; Trull Silvestre, José Francisco; Cojocaru, Crina; Neshev, Dragomir N.; Krolikowski, Wieslaw; Vilaseca Alavedra, Ramon; Staliunas, Kestutis; Kivshar, Yu. (2009)
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      We study theoretically and experimentally the second harmonic generation in nonlinear crystals with random distribution of ferroelectric domains. We show that the specific features of disordered domain structure greatly ...
    • The role of the phase locking phenomenon in the second and third harmonics cavity localization 

      Roppo, Vito; Cojocaru, Crina; D'Agunaro, G.; Ranieri, F.; Raj, R.; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Scalora, M. (2009)
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      We theoretically and experimentally study how the phase-locking mechanism changes effective dispersion of the medium at the harmonic frequencies making them become localized inside a opaque cavity designed to be resonant ...
    • Ultrashort pulse chirp determination via transverse auto-correlation in SBN crystal 

      Wang, Bingxia; Cojocaru, Crina; Inigo Sola, Inigo Sola; Wieslaw Krolikowski, Wieslaw Krolikowski; Yan Sheng, Yan Sheng; Vilaseca Alavedra, Ramon; Trull Silvestre, José Francisco (2015)
      Comunicació de congrés
      Accés restringit per política de l'editorial
      We determine the different initial chirp parameters of ultra-short pulses down to 30 fs via single-shot transverse auto-correlation method based on transverse second harmonic generation in SBN crystal with random distribution ...
    • Ultrashort pulse chirp measurement via transverse second-harmonic generation in strontium barium niobate crystal 

      Trull Silvestre, José Francisco; Sola, Ïñigo; Wang, Bingxia; Parra, Albert; Krolikowski, W.; Sheng, Y.; Vilaseca Alavedra, Ramon; Cojocaru, Crina (2015-06-01)
      Article
      Accés obert
      Pulse compression in dispersive strontium barium niobate crystal with a random size and distribution of the anti-parallel orientated nonlinear domains is observed via transverse second harmonic generation. The dependence ...