Ara es mostren els items 30-49 de 65

    • 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 ...
    • Laser Ultrasound Inspection Based on Wavelet Transform and Data Clustering for Defect Estimation in Metallic Samples 

      Mohamed Selim, Hossameldin; Delgado Prieto, Miquel; Trull Silvestre, José Francisco; Romeral Martínez, José Luis; Cojocaru, Crina (Multidisciplinary Digital Publishing Institute (MDPI), 2019-01-30)
      Article
      Accés obert
      Laser-generated ultrasound is a modern non-destructive testing technique. It has been investigated over recent years as an alternative to classical ultrasonic methods, mainly in industrial maintenance and quality control ...
    • Material defect reconstruction by non-destructive testing with laser induced ultrasonics 

      Mohamed Selim, Hossameldin; Delgado Prieto, Miquel; Trull Silvestre, José Francisco; Pico Vila, Rubén; Cojocaru, Crina (Institute of Physics (IOP), 2018)
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      Aligned with current research efforts and industrial applications on nondestructive testing, in this work, a hybrid system combining remotely induced laser ultrasonics with conventional transducer detection is studied for ...
    • Nonlinear duffing oscillator model for third harmonic generation 

      Scalora, Michael; Vincenti, M. A.; Ceglia, Domenico de; Cojocaru, Crina; Grande, Manuel; Haus, J.W. (2015-10-01)
      Article
      Accés obert
      We employ a classical, nonlinear Lorentz-Duffing oscillator model to predict third harmonic conversion efficiencies in the ultrafast regime, from a variety of metal nanostructures, including smooth, isolated metal layers, ...
    • Nonspreading Light Pulses in Photonic Crystals 

      Staliunas, Kestutis; Serrat Jurado, Carles; Herrero Simon, Ramon; Cojocaru, Crina; Trull Silvestre, José Francisco (2005-05)
      Report de recerca
      Accés obert
      We investigate propagation of light pulses in photonic crystals in the vicinity of the zero-diffraction point. We show that Gaussian pulses due to nonzero width of their spectrum spread weakly in space and time during the ...
    • 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 harmonic generation in the opaque region of GaAs 

      Cojocaru, Crina; Rodríguez Suñé, Laura; Escalora, M.; Trull Silvestre, José Francisco (Institute of Electrical and Electronics Engineers (IEEE), 2019)
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      We demonstrate second and third harmonic generation from a GaAs substrate, well-below the absorption edge, in both transmission and reflection geometries. The pump is tuned at 1064 nm, in the transparency range, while the ...
    • 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 ...
    • Phononic crystal device as a self-collimator for laser induced ultrasound 

      Mohamed Selim, Hossameldin; Pico Vila, Rubén; Trull Silvestre, José Francisco; Delgado Prieto, Miquel; Cojocaru, Crina (Sociedad Española de Acústica (SEA), 2018)
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      Laser generated ultrasound has gained interest as an alternative source of ultrasound thanks to its remote operation, high resolution in the excitation area and broad frequency band. However, one of its drawbacks is the ...
    • Photonic crystal spatial filtering in broad aperture diode laser 

      Gawali, Sandeep Babu; Gailevicius, Darius; Garre Werner, Guillermo; Purlys, Vytautas; Cojocaru, Crina; Trull Silvestre, José Francisco; Montiel Ponsoda, Joan; Staliunas, Kestutis (2019-10-02)
      Article
      Accés obert
      Broad aperture semiconductor lasers usually suffer from low spatial quality of the emitted beams. Due to the highly compact character of such lasers, the use of conventional intracavity spatial filters is problematic. We ...
    • 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. ...
    • Resonant, broadband, and highly efficient optical frequency conversion in semiconductor nanowire gratings at visible and UV wavelengths 

      Escalora, M.; Trull Silvestre, José Francisco; Cojocaru, Crina; Vincenti, M. A.; Carletti, Luca; Ceglia, Domenico de; Akozbek, Neset; De Angelis, C. (2019-08-01)
      Article
      Accés restringit per política de l'editorial
      Using a hydrodynamic approach, we examine bulk- and surface-induced second- and third-harmonic generationfrom semiconductor nanowire gratings having a resonant nonlinearity in the absorption region. We demonstrateresonant, ...
    • Retrieving linear and nonlinear optical dispersions of matter: combined experiment-numerical ellipsometry in silicon, gold and indium tin oxide 

      Rodríguez Suñé, Laura; Trull Silvestre, José Francisco; Akozbek, Neset; Ceglia, Domenico de; Vincenti, M. A.; Scalora, Michael; Cojocaru, Crina (2021-09-17)
      Article
      Accés obert
      We have presented a combined experimental and numerical method that can be used to predict complex nonlinear dispersion curves in almost any material, based exclusively on the experimental determination of harmonic generation ...
    • Second and third harmonic generation from gold nanolayers: experiment versus theory 

      Rodríguez Suñé, Laura; Trull Silvestre, José Francisco; Akozbek, Neset; Ceglia, Domenico de; Vincenti, M. A.; Scalora, Michael; Cojocaru, Crina (EPJ Web of Conferences, 2021)
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      The use of semiconductors, metals, or ordinary dielectrics in the process of fabrication of nanodevices is at the front edge of nowadays technology, exploiting the properties of light propagation and localization at ...
    • 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 from an ITO nanolayer: experiment versus theory 

      Rodríguez Suñé, Laura; Scalora, Michael; Johnson, Allan; Cojocaru, Crina; Akozbek, Neset; Coppens, Zachary; Pérez Salinas, Daniel; Wall, Simon; Trull Silvestre, José Francisco (International Society for Photo-Optical Instrumentation Engineers (SPIE), 2020)
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      We report a comparative experimental and theoretical study of second harmonic generation from a 20nm-thick indium tin oxide nanolayer in the proximity of the epsilon-near-zero condition. We record the efficiency of 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)
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      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)
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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 ...
    • Signatures of light-beam spatial filtering in a three-dimensional photonic crystal 

      Maigyte, Lina; Gertus, T.; Peckus, Martynas; Trull Silvestre, José Francisco; Sirutkaitis, Valdas; Cojocaru, Crina; Staliunas, Kestutis (2010-08-13)
      Article
      Accés obert
      We report experimental evidence of spatial filtering of light beams by three-dimensional, low-refraction-index-contrast photonic crystals. The photonic crystals were fabricated in a glass bulk, where the refraction index ...
    • Single-shot d-scan technique for ultrashort laser pulse characterization using transverse second-harmonic generation in random nonlinear crystals 

      Cojocaru, Crina; Trull Silvestre, José Francisco; Romero Muñiz, Rosa María; Sola Larrañaga, Iñigo Juan (2020-07-15)
      Article
      Accés obert
      We demonstrate a novel dispersion-scan (d-scan) scheme for single-shot temporal characterization of ultrashort laser pulses. The novelty of this method relies on the use of a highly dispersive crystal featuring antiparallel ...