Now showing items 21-40 of 58

    • Fully Noncontact Hybrid NDT for 3D Defect Reconstruction Using SAFT Algorithm and 2D Apodization Window 

      Mohamed Selim, Hossameldin; Trull Silvestre, José Francisco; Delgado Prieto, Miquel; Pico Vila, Rubén; Romeral Martínez, José Luis; Cojocaru, Crina (Multidisciplinary Digital Publishing Institute (MDPI), 2019-05-08)
      Article
      Open Access
      Nondestructive testing of metallic objects that may contain embedded defects of different sizes is an important application in many industrial branches for quality control. Most of these techniques allow defect detection ...
    • Harmonic generation at the nanoscale in strategic materials for nanophotonics 

      Rodríguez Suñé, Laura; Trull Silvestre, José Francisco; Scalora, Michael; Akozbek, Neset; Cojocaru, Crina (International Society for Photo-Optical Instrumentation Engineers (SPIE), 2021)
      Conference report
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      The use of semiconductors, metals and conductive oxides in the process of fabrication of actual nano devices is at the front edge of nowadays technology, exploiting the properties of light propagation and localization at ...
    • Harmonic generation from gold nanolayers: bound and hot electron contributions 

      Rodríguez Suñé, Laura; Trull Silvestre, José Francisco; Cojocaru, Crina; Akozbek, Neset; Ceglia, Domenico de; Vincenti, M. A.; Scalora, Michael (International Society for Photo-Optical Instrumentation Engineers (SPIE), 2021)
      Conference report
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      Currently, nanostructures are routinely fabricated and integrated in different photonic devices for a variety of purposes and applications. For instance, in order to engineer properly nano-antennas or filters, it is important ...
    • Harmonic generation from gold nanolayers: bound and hot electron contributions to nonlinear dispersion 

      Rodríguez Suñé, Laura; Trull Silvestre, José Francisco; Cojocaru, Crina; Akozbek, Neset; Ceglia, Domenico de; Vincenti, M. A.; Scalora, Michael (2021-03-15)
      Article
      Open Access
      Understanding how light interacts with matter at the nanoscale is pivotal if one is to properly engineer nano-antennas, filters and other devices whose geometrical features approach atomic size. We report experimental ...
    • 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 ...
    • 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
      Open Access
      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)
      Conference report
      Open Access
      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
      Open Access
      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)
      External research report
      Open Access
      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
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      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)
      Conference report
      Open Access
      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)
      Conference report
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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)
      Conference report
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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
      Open Access
      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
      Open Access
      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
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      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, ...
    • 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)
      Conference report
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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)
      Conference report
      Open Access
      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)
      Conference report
      Open Access
      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 ...