Now showing items 21-40 of 115

    • 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
      Restricted access - publisher's policy
      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 ...
    • Diffractive effects in 1D and 2D gain/loss periodic spatial modulated materials 

      Herrero Simon, Ramon; Botey Cumella, Muriel; Staliunas, Kestutis (IEEE Press. Institute of Electrical and Electronics Engineers, 2010)
      Conference report
      Restricted access - publisher's policy
      The propagation of light through materials with periodically modulated gain can present different effects that are analyzed in the paper. The characterization of these gain/loss metamaterials (GLM) with a two-dimensional ...
    • Directional invisibility by genetic optimization 

      Bor, Emre; Babayigit, Ceren; Kurt, H.; Staliunas, Kestutis; Turduev, M. (2018-11-26)
      Article
      Open Access
      In this Letter, the design of a directional optical cloaking by a genetic algorithm is proposed and realized experimentally. A three-dimensional finite-difference time-domain method is combined with the genetic optimization ...
    • Directionality fields generated by a local Hilbert transform 

      Ahmed, W. W.; Herrero Simon, Ramon; Botey Cumella, Muriel; Hayran, Zeki; Kurt, Hamza; Staliunas, Kestutis (American Physical Society, 2018-03-15)
      Article
      Open Access
      We propose an approach based on a local Hilbert transform to design non-Hermitian potentials generating arbitrary vector fields of directionality, ¿p(¿r), with desired shapes and topologies. We derive a local Hilbert ...
    • Dispersion management in spatially modulated broad band semiconductors 

      Herrero Simon, Ramon; Botey Cumella, Muriel; Khumar, N.P.; Staliunas, Kestutis (IEEE, 2011)
      Conference report
      Restricted access - publisher's policy
    • Dissipation Induced Modulation Instability: New Applications for Frequency Combs and Pulses Generation 

      Perego, A.M.; Turitsyn, S.K.; Staliunas, Kestutis (Institute of Electrical and Electronics Engineers (IEEE), 2018-11-15)
      Conference report
      Restricted access - publisher's policy
      We present a new technique based on a dissipation induced modulation instability, caused by unbalanced spectral dissipation for signal and idler waves, with applications in amplifiers and parametric oscillators but especially ...
    • Enhanced transmission band in periodic media with loss modulation 

      Cebrecos, A.; Pico Vila, Rubén; Romero García, Vicenç; Yasser, A.M.; Maigyte, Lina; Herrero Simon, Ramon; Botey Cumella, Muriel; Sánchez Morcillo, Victor José; Staliunas, Kestutis (2014-11-17)
      Article
      Open Access
      We study the propagation of waves in a periodic array of absorbing layers. We report an anomalous increase of wave transmission through the structure related to a decrease of the absorption around the Bragg frequencies. ...
    • Enhancement of sound by soft reflections in exponentially chirped crystals 

      Cebrecos, A.; Pico Vila, Rubén; Sánchez Morcillo, Victor José; Staliunas, Kestutis; Romero García, Vicenç; Garcia Raffi, Luis Miguel (2014-12-01)
      Article
      Open Access
      The enhancement of sound inside a two dimensional exponentially chirped crystal during the soft reflections of waves is experimentally and theoretically explored in this work. The control of this enhancement is achieved ...
    • Experimental demonstration of bistable phase locking in a photorefractive oscillator 

      Kolpakov, S.; Silva, F.; de Valcarcel, German J.; Roldán, Eugenio; Staliunas, Kestutis (2012)
      Article
      Open Access
      We report experimental evidence of bistable phase locking in nonlinear optics, in particular, in a photorefractive oscillator emitting in few transverse modes. Bistable phase locking is a recently proposed method for ...
    • Experimental demonstration of phase bistability in a broad-area optical oscillator with injected signal 

      Martinez Lorente, R.; Esteban Martin, A.; Roldan, E.; Staliunas, Kestutis; Valcarcel Gonzalvo, Germán José de; Silva, F. (2015-11-30)
      Article
      Open Access
    • Experimental observation of flat focusing mirror based on photonic jet effect 

      Minin, Igor V.; Liu, Cheng-Yang; Yang, Yu-Chih; Staliunas, Kestutis; Minin, Oleg V. (Nature, 2020-12-01)
      Article
      Open Access
      In this work, we experimentally demonstrate that a thin rectangle dielectric-metal structure can have a function of a flat focusing mirror based on photonic jet effect in reflection mode. Using polydimethylsiloxane (PDMS) ...
    • Far-field narrowing in spatially modulated broad-area edge-emitting semiconductor amplifiers 

      Radziunas, Mindaugas; Herrero Simon, Ramon; Botey Cumella, Muriel; Staliunas, Kestutis (2015-05-01)
      Article
      Open Access
      We perform a detailed theoretical analysis of the far-field narrowing in broad-area edge-emitting semiconductor amplifiers that are electrically injected through contacts periodically modulated in both longitudinal and ...
    • Field concentration by Axisymmetric local PT-symmetry 

      Ahmed Waseem, Waqas Waseem; Botey Cumella, Muriel; Herrero Simon, Ramon; Staliunas, Kestutis (2016)
      Conference report
      Open Access
      We propose a new class of systems holding PT-symmetry only locally; the potential fulfills: U(r-r0)=U*(-r+r0 ) in a small neighborhood of any point r0, whereas on a global scale the system is only Parity symmetric: ...
    • 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 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 by periodic loss-modulated materials 

      Pradeep Kumar, Nikhil; Herrero Simon, Ramon; Botey Cumella, Muriel; Staliunas, Kestutis (2013-09-23)
      Article
      Open Access
      We propose a flat lensing effect using a periodic loss-modulated material. In particular, we consider a two-dimensional square and rhombic arrangement of lossy cylinders embedded in a host media with the same refractive ...
    • 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 ...
    • Focalization of evanescent beams 

      Botey Cumella, Muriel; Cheng, Yu Chieh; Herrero Simon, Ramon; Romero García, V.; Pico, R.; Sánchez Morcillo, V. J.; Staliunas, Kestutis (IEEE, 2012)
      Conference lecture
      Restricted access - publisher's policy
      We predict and show the existence of unlocked evanescent waves in two dimensional periodic structures. In a one dimensional periodic structure an evanescent mode are located either at the center or at the boundary of the ...
    • 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 ...
    • Formation of collimated sound beams by three-dimensional sonic crystals 

      Cebrecos, A.; Romero García, V.; Pico, R.; Pérez Arjona, I; Espinosa Duró, Virginia; Sánchez Morcillo, V. J.; Staliunas, Kestutis (American Institute of Physics (AIP), 2012)
      Article
      Open Access
      A theoretical and experimental study of the propagation of sound beams in- and behind three-dimensional sonic crystals at frequencies close to the band edges is presented. An efficient collimation of the beam behind the ...