UPCommons està en procés de migració del dia 10 fins al 14 Juliol. L’autentificació està deshabilitada per evitar canvis durant aquesta migració.

Browsing by Author "Cojocaru, Crina"Més informacióMés informació

Now showing items 21-40 of 67

    • 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)
      Conference report
      Restricted access - publisher's policy
      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
      Open Access
      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
      Open Access
      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
      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
      Restricted access - publisher's policy
      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
      Restricted access - publisher's policy
      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 from silicon membranes at visible and ultraviolet wavelengths 

      Anson Hallman, Kent; Rodríguez Suñé, Laura; Trull Silvestre, José Francisco; Cojocaru, Crina; Vincenti, Maria Antonietta; Akozbek, Neset; Vilaseca, Ramon; Scalora, Michael (2023-01-16)
      Article
      Open Access
      Nonlinear silicon photonics offers unique abilities to generate, manipulate and detect optical signals in nano-devices, with applications based on field localization and large third order nonlinearity. However, at the ...

    • 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 ...

    • High-harmonic generation from subwavelength silicon films 

      Anson Hallman, Kent; Stengel, Sven; Wallace, Jaffray; Belli, Federico; Ferrera, Marcello; Vincenti, Maria Antonietta; Ceglia, Domenico de; Kivshar, Yu.; Akozbek, Neset; Mukhopadhyay, Shroddha; Trull Silvestre, José Francisco; Cojocaru, Crina; Scalora, Michael (2025-01-16)
      Article
      Open Access
      Recent years have witnessed significant developments in the study of nonlinear properties of various materials at the nanoscale. Often, experimental results on harmonic generation are reported without the benefit of suitable ...

    • 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)
      Conference report
      Restricted access - publisher's policy
      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
      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)
      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
      Restricted access - publisher's policy
      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
      Restricted access - publisher's policy
      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
      Restricted access - publisher's policy
      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 ...