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Ara es mostren els items 8-27 de 65

    • Defect reconstruction by non-destructive testing with laser induced ultrasonic detection 

      Mohamed Selim, Hossameldin; Delgado Prieto, Miquel; Trull Silvestre, José Francisco; Pico Vila, Rubén; Romeral Martínez, José Luis; Cojocaru, Crina (2020-02)
      Article
      Accés obert
      This work envisages a detailed study of two-dimensional defect localization and reconstruction, using laser generated ultrasound and its application as a remotely controlled non-destructive testing method. As an alternative ...

    • 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)
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      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 ...

    • Directional ultrasound source for solid materials inspection: diffraction management in a metallic phononic crystal 

      Mohamed Selim, Hossameldin; Pico Vila, Rubén; Trull Silvestre, José Francisco; Delgado Prieto, Miquel; Cojocaru, Crina (Multidisciplinary Digital Publishing Institute (MDPI), 2020-10-29)
      Article
      Accés obert
      In this work, we numerically investigate the diffraction management of longitudinal elastic waves propagating in a two-dimensional metallic phononic crystal. We demonstrate that this structure acts as an “ultrasonic lens”, ...

    • Domain statistics analysis of random nonlinear crystals via second harmonic generation 

      Wang, Bingxia; Cojocaru, Crina; Krolikowski, Wieslaw; Switowski, K; Yan Sheng, Yan Sheng; Akhouayri, H.; Vilaseca Alavedra, Ramon; Scalora, Michael; Trull Silvestre, José Francisco (Institute of Electrical and Electronics Engineers (IEEE), 2017)
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      We demonstrate an indirect non-destructive optical method for the characterization of ferroelectric domain size and distribution based on the analysis of the generated second harmonic spatial distribution. This method is ...

    • Electrodynamics of conductive oxides: intensity-dependent anisotropy, reconstruction of the effective dielectric constant, and harmonic generation 

      Scalora, Michael; Trull Silvestre, José Francisco; Ceglia, Domenico de; Vincenti, M. A.; Akozbek, Neset; Coppens, Zachary; Rodríguez Suñé, Laura; Cojocaru, Crina (2020-05-13)
      Article
      Accés obert
      We study electromagnetic pulse propagation in an indium tin oxide nanolayer in the linear and nonlinear regimes. We use the constitutive relations to reconstruct the effective dielectric constant of the medium, and show ...

    • 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
      Accés obert
      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 ...

    • Experiència de pràctiques personalitzades i xerrades professionals en el màster interuniversitari en fotònica 

      Royo Royo, Santiago; Vilaseca Ribalta, Ramon; Laguarta Bertran, Ferran; Pizarro Bondia, Carlos; Cojocaru, Crina; Trull Silvestre, José Francisco; Lázaro, José; Prat, Josep; Orriols i Tubella, Gaspar; Juvells, Ignasi (Universitat Politècnica de Catalunya. Institut de Ciències de l'Educació, 2010-02-11)
      Comunicació de congrés / Text en actes de congrés
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      S’ha posat en funcionament una doble estratègia innovadora orientada a potenciar competències transversals en el Màster en Fotònica. Per una banda, s’ha engegat una assignatura de pràctiques personalitzades, que ...

    • Experimental and theoretical study of second and third harmonic generation in amorphous silicon 

      Rodríguez Suñé, Laura; Scalora, Michael; Cojocaru, Crina; Akozbek, Neset; Vilaseca Alavedra, Ramon; Trull Silvestre, José Francisco (International Society for Photo-Optical Instrumentation Engineers (SPIE), 2022)
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      We report contrasted experimental and theoretical results on second and third harmonic generation from an amorphous silicon nanolayer. We perform this study by analysing the harmonic optical signals generated when fs and ...

    • Experimental and Theoretical Study of Second Harmonic Generation from an ITO Nanolayer 

      Rodríguez Suñé, Laura; Scalora, Michael; Johnson, Allan; Cojocaru, Crina; Akozbek, Neset; Coppens, Zachary; Pérez Salinas, Daniel; Wall, Simon; Trull Silvestre, José Francisco (Institute of Electrical and Electronics Engineers (IEEE), 2020)
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      We present an experimental study of second harmonic generation from a 20nm-thick indium tin oxide layer in the proximity of its epsilon-near-zero condition. We report measurements of second harmonic efficiencies as a ...

    • Ferroelectric domain engineering by focused infrared femtosecond pulses 

      Chen, Xin; Karpinski, Pawel; Shvedov, Vladlen; Koynov, Kaloian; Wang, Bingxia; Trull Silvestre, José Francisco; Cojocaru, Crina; Krolikowski, Wieslaw; Sheng, Yan (2015-10-05)
      Article
      Accés obert
      We demonstrate infrared femtosecond laser-induced inversion of ferroelectric domains. This process can be realised solely by using tightly focused laser pulses without application of any electric field prior to, in conjunction ...

    • Ferroelectric domain patterning with ultrafast light 

      Chen, Xin; Shvedov, Vladlen; Karpinski, Pawel; Koynov, Kaloian; Boes, A.; Mitchell, A.; Trull Silvestre, José Francisco; Cojocaru, Crina; Krolikowski, Wieslaw; Sheng, Yan (2016-12-01)
      Article
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    • 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
      Accés obert
      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 ...

    • 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 ...

    • Flat lensing in the visible frequency range by woodpile photonic crystals 

      Maigyte, Lina; Purlys, Vytautas; Trull Silvestre, José Francisco; Peckus, Martynas; Cojocaru, Crina; Gailevicius, Darius; Malinauskas, Mangirdas; Staliunas, Kestutis (2013-07-15)
      Article
      Accés obert
      We experimentally demonstrate full two-dimensional focalization of light beams at visible frequencies by a three-dimensional woodpile photonic crystal. The focalization (the flat lensing) with focal distances of the order ...

    • Formation of collimated beams behind the woodpile photonic crystal 

      Trull Silvestre, José Francisco; Maigyte, Lina; Malinauskas, Mangirdas; Mizeikis, Vygantas; Juodkazis, Saulius; Cojocaru, Crina; Rutkauskas, Marius; Peckus, Martynas; Sirutkaitis, Valdas; Staliunas, Kestutis (2011-09-09)
      Article
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      We experimentally observe formation of narrow laser beams behind the woodpile photonic crystal, when the beam remains well collimated in free propagation behind the crystal. We show that the collimation depends on the input ...

    • 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
      Accés obert
      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)
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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)
      Text en actes de congrés
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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
      Accés obert
      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
      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 ...