Now showing items 1-20 of 49

  • Acoustically penetrable sonic crystals based on fluid-like scatterers 

    Cebrecos, A.; Romero García, Vicenç; Pico Vila, Rubén; Sánchez Morcillo, Victor José; Botey Cumella, Muriel; Herrero Simon, Ramon; Cheng, Yu Chieh; Staliunas, Kestutis (2015-01-21)
    Article
    Open Access
    We propose a periodic structure that behaves as a fluid-fluid composite for sound waves, where the building blocks are clusters of rigid scatterers. Such building-blocks are penetrable for acoustic waves, and their properties ...
  • A New learning experience: voluntary preparatory course for the bachelor’s degree in engineering 

    Botey Cumella, Muriel; Alcaraz, Olga (Universitat Politècnica de Catalunya. Institut de Ciències de l'Educació, 2012-03)
    Article
    Open Access
    This paper reports on a new experience carried out at school associated with the Technical University of Catalonia, Universitat Politècnica de Catalunya (UPC) in September 2010. The aim is to describe the organization, ...
  • Anomalous group velocity at the high energy range of real 3D photonic nanostructures 

    Botey Cumella, Muriel; Martorell Pena, Jordi (SPIE-The International Society for Optical Engineering, 2010-04-12)
    Conference report
    Open Access
    We perform a theoretical study on the group velocity for finite thin artificial opal slabs made of a reduced number of layers in the spectral range where the light wavelength is on the order of the lattice parameter. The ...
  • Asymmetric light transmission by using 2D PT-symmetric photonic nanostructure 

    Turduev, M.; Botey Cumella, Muriel; Herrero Simon, Ramon; Kurt, H.; Staliunas, Kestutis; Giden, I. (Wiley-IEEE Press, 2015)
    Conference report
    Restricted access - publisher's policy
    We propose for the first time a simple realization of a two-dimensional Parity-Time symmetric hexagonal shaped photonic structure composed of honeycomb lattice. The structure has a symmetric periodic modulation of the ...
  • Asymmetric light transmission in PT-Symmetric microring resonators 

    Giden, I.; Dadashi, Kh.; Botey Cumella, Muriel; Herrero Simon, Ramon; Staliunas, Kestutis; Kurt, Hamza (2016-03-15)
    Article
    Restricted access - publisher's policy
    We propose a new type of add-drop microring resonator made of gain and loss materials. Microring resonators are compact, narrow band, and optical channel dropping filters. In such linear systems, light transmission to ...
  • Asymmetric transmission from a 2D PT-symmetric honeycomb nanostructure 

    Botey Cumella, Muriel; Herrero Simon, Ramon; Turduev, M.; Zhao, D.; Giden, I.; Kurt, H.; Staliunas, Kestutis (Institute of Electrical and Electronics Engineers (IEEE), 2014)
    Conference lecture
    Restricted access - publisher's policy
    We propose a simple realization of a 2-dimensonal (2D) PT-symmetric photonic structure: a honeycomb arrangement of alternating cylinders with gain or loss in a dielectric background. The structure provides a periodic ...
  • Axisymmetric photonic structures with PT-symmetry 

    Ahmed Waseem, Waqas Waseem; Herrero Simon, Ramon; Botey Cumella, Muriel; Staliunas, Kestutis (International Society for Photo-Optical Instrumentation Engineers (SPIE), 2016)
    Conference report
    Open Access
    PT-symmetric structures in photonic crystals, combining refractive index and gain-loss modulations is becoming a research field with increasing interest due to the light directionality induced by these particular potentials. ...
  • Beam shaping in spatially modulated broad-area semiconductor amplifiers 

    Herrero Simon, Ramon; Botey Cumella, Muriel; Radziunas, Mindaugas; Staliunas, Kestutis (2012-12-15)
    Article
    Open Access
    We propose and analyze a beam-shaping mechanism that in broad-area semiconductor amplifiers occurs due to spatial pump modulation on a micrometer scale. The study, performed under realistic parameters and conditions, ...
  • Chiral modes in 2D PT-symmetric nanostructures 

    Botey Cumella, Muriel; Herrero Simon, Ramon; Turduev, M.; Kurt, H.; Staliunas, Kestutis (Springer International Publishing, 2015-11-15)
    Part of book or chapter of book
    Restricted access - publisher's policy
    We propose the stabilization of the output beam of Broad Area Semiconductor (BAS) amplifiers through the introduction of a spatially periodic modulated potential. We show that a periodic modulation of the pump profile in ...
  • Control and enhancement of beam quality of broadarea semiconductor devices and arrays by multimode interference couplers and two-dimensional gain modulation 

    Murad, M.; Sorel, M.; Herrero Simon, Ramon; Botey Cumella, Muriel; Marsh, J.H.; Staliunas, Kestutis (Institute of Electrical and Electronics Engineers (IEEE), 2013)
    Conference report
    Open Access
    It is proposed to control the beam quality of broad-area semiconductor devices by two-dimensional structuring enforcing phase coherence across the device. First results based on MMI couplers are presented.
  • 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 ...
  • 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
  • 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. ...
  • 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 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 ...
  • 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 ...
  • Intrinsic beam shaping mechanism in spatially modulated broad area semiconductor amplifiers 

    Radziunas, Mindaugas; Botey Cumella, Muriel; Herrero Simon, Ramon; Staliunas, Kestutis (2013-09-23)
    Article
    Open Access
  • Invisibility on demand based on a generalized Hilbert transform 

    Hayran, Zeki; Herrero Simon, Ramon; Botey Cumella, Muriel; Kurt, Hamza; Staliunas, Kestutis (American Physical Society (APS), 2018-07-12)
    Article
    Open Access
    We propose a feasible invisibility approach to suppress the scattering of waves from or to given directions and for particular frequencies, i.e., invisibility on demand. We derive a generalized Hilbert transform for a ...