Now showing items 1-20 of 30

  • Beam focalization by chirped mirrors 

    Cheng, Yu Chieh; Peckus, Martynas; Kicas, Simonas; Trull Silvestre, José Francisco; Cojocaru, Crina; Vilaseca Alavedra, Ramon; Drazdys, Ramutis; Staliunas, Kestutis (Optical Society of American (OSA), 2014)
    Conference report
    Restricted access - confidentiality agreement
    A novel application of chirped dielectric mirrors for narrow beam focalization is proposed and demonstrated numerically and experimentally. Analogy to temporal dispersion compensation by chirped dielectric mirrors is discussed.
  • Beam focalization in reflection from flat dielectric subwavelength gratings 

    Cheng, Yu Chieh; Zeng, H; Trullàs Simó, Joaquim; Cojocaru, Crina; Malinauskas, Mangirdas; Jukna, T; Wiersma, D.S.; Staliunas, Kestutis (2014-10-15)
    Article
    Restricted access - publisher's policy
    We experimentally demonstrate the recently predicted effect of near-field focusing for light beams from flat dielectric subwavelength gratings (SWGs). This SWGs were designed for visible light 532 nm and fabricated by ...
  • Broadband third harmonic generation in quadratic media with disordered ferroelectric domains 

    Kalinowski, K.; Roppo, Vito; Wang, W.; Neshev, Dragomir N.; Kong, Y.; Cojocaru, Crina; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Staliunas, Kestutis; Krolikowski, Wieslaw; Kivshar, Yu. (2010)
    Conference report
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    We study nonlinear frequency generation in media with random ferroelectric domain structure. We show that randomness enables one to realize broadband third harmonic generation via cascading of two second order quasi-phase ...
  • Cavity behavior of second and third harmonic inhomogeneous solutions of Maxwell’s equations 

    Roppo, Vito; Cojocaru, Crina; Trull Silvestre, José Francisco; Vilaseca Alavedra, Ramon; Scalora, M. (2010)
    Article
    Restricted access - publisher's policy
    We study second and third harmonic generation of ultrashort pulses in a cavity environment and focus on the role of a phase locking phenomenon that causes the pump to trap and drag the generated harmonic fields. The results ...
  • Comparative analysis of ferroelectric domain statistics via nonlinear diffraction in random nonlinear materials 

    Wang, Bin; Switowski, K; Cojocaru, Crina; Roppo, V; Sheng, Yan; Escalora, M.; Kisielewski, J.; Pawlak, D.; Vilaseca Alavedra, Ramon; Akhouayri, H.; Krolikowski, Wieslaw; Trull Silvestre, José Francisco (2018-01-22)
    Article
    Open Access
    We present an indirect, non-destructive optical method for domain statistic characterization in disordered nonlinear crystals having homogeneous refractive index and spatially random distribution of ferroelectric domains. ...
  • Controllable light diffraction in woodpile photonic crystals filled with liquid crystal 

    Ho, Chih-Hua; Cheng, Yu Chieh; Maigyte, Lina; Zeng, H; Trull Silvestre, José Francisco; Cojocaru, Crina; Wiersma, D.S.; Staliunas, Kestutis (2015-01-12)
    Article
    Open Access
    An approach to switching between different patterns of light beams transmitted through the woodpile photonic crystals filled with liquid crystals is proposed. The phase transition between the nematic and isotropic liquid ...
  • 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)
    Conference lecture
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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 ...
  • 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
    Open Access
    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)
    Conference lecture / Conference report
    Open Access
    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 ...
  • 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
    Open Access
    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
    Open Access
  • 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
    Open Access
    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 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 ...
  • 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 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 ...
  • 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
    Restricted access - publisher's policy
    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)
    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 ...
  • 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
    Restricted access - publisher's policy
    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
    Open Access
    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 ...