Now showing items 1-20 of 81

    • 3D metallo-dielectric structures combining electrochemical and electroplating techniques 

      Hernández Díaz, David; Lange, D.; Todorov Trifonov, Trifon; Garin Escriva, Moises; García Molina, Francisco Miguel; Rodríguez Martínez, Ángel; Alcubilla González, Ramón (2010-06)
      Article
      Restricted access - publisher's policy
      Three-dimensional (3D) periodic nickel micro-structures with a periodicity of 4 μm and high number of structural periods were fabricated by electrodeposition. Macroporous silicon, consisting of periodic arrays of sine-wave ...
    • Absorption mechanisms in macroporous silicon photonic crystals 

      Segura García, Daniel; Cardador Maza, David; Rodríguez Martínez, Ángel; Llorca Piqué, Jordi (Elsevier, 2019-01-01)
      Article
      Open Access
      We investigate the large differences classically found in literature between theoretical and empirical results in the optical characterization of macroporous silicon photonic crystals. Mainly, we study the impact of two ...
    • Al2O3/TiO2 inverse opals from electrosprayed self-assembled templates 

      Coll, Arnau; Bermejo Broto, Sandra; Hernández, David; Castañer Muñoz, Luis María (2018-01-19)
      Article
      Open Access
      The fabrication of high optical quality inverse opals is challenging, requiring large size, three-dimensional ordered layers of high dielectric constant ratio. In this article, alumina/TiO2–air inverse opals with a 98.2% ...
    • Analysis of photonic band gaps in two-dimensional photonic crystals with rods covered by a thin interfacial layer 

      Todorov Trifonov, Trifon; Marsal, L F; Rodríguez Martínez, Ángel; Pallarès Marzal, Josep; Alcubilla González, Ramón (2004-11)
      Article
      Restricted access - publisher's policy
      We investigate different aspects of the absolute photonic band gap (PBG) formation in two-dimensional photonic structures consisting of rods covered with a thin dielectric film. Specifically, triangular and honeycomb ...
    • Angular filtering by Bragg photonic microstructures fabricated by physical vapour deposition 

      Grineviciute, Lina; Babayigit, Ceren; Gailevicius, Darius; Bor, Emre; Turduev, Mirbek; Purlys, Vytautas; Tolenis, Tomas; Kurt, Hamza; Staliunas, Kestutis (2019-07-01)
      Article
      Open Access
      We propose and experimentally demonstrate spatial filtering by photonic crystals in a Bragg configuration. Compared to the Laue configuration, where spatial filtering was already demonstrated before, the Bragg configuration ...
    • Anomalous diffusion in axismmetric photonic crystals 

      Sardà Ventosa, Meritxell (Universitat Politècnica de Catalunya, 2014-12-09)
      Bachelor thesis
      Restricted access - author's decision
      In the proposed work such structures are to be numerically simulated in order to justify the expected behaviour, as well as measured experimentally. The samples for the experimental part of the study are being fabricated ...
    • 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 effect based on an evolutionary optimized semi-Dirac cone dispersion photonic structure 

      Bor, Emre; Turduev, Mirbek; Yasa, Utku Görkem; Kurt, Hamza; Staliunas, Kestutis (American Physical Society (APS), 2018-12-10)
      Article
      Open Access
      In this paper, we present the numerical and experimental demonstration of asymmetric light transmission by a compact photonic crystal (PC) structure, which sustains semi-Dirac cone dispersion. The semi-Dirac point is ...
    • 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 ...
    • Au/TiO2 2D-photonic crystals as UV–visible photocatalysts for H2 production 

      Torras, Miquel; Molet, Pau; Soler Turu, Lluís; Llorca Piqué, Jordi; Roig, Anna; Mihi, Agustin (2022-02-10)
      Article
      Restricted access - publisher's policy
      Noble metal decoration of wideband gap semiconductors enables the excitation of surface plasmons in the visible range that upon relaxation generate hot carriers used for catalysis. However, this strategy leads to photocatalytic ...
    • 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. ...
    • Bandgap widening in macroporous silicon photonic crystals by multiperiodic structures 

      Segura García, Daniel; Cardador Maza, David; Vega d'Aurelio, Davide; Santos Blanco, M. Concepción; Dios Otín, Víctor Federico; Rodríguez Martínez, Ángel (Institute of Physics (IOP), 2018-05-14)
      Article
      Open Access
      Large bandgaps with low transmission in 3D macroporous silicon photonic crystals have been proved as an interesting technology for the development of optical filters and spectroscopic MIR gas sensors. The aim of this study ...
    • 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 ...
    • Bound states in the continuum in a two-dimensional PT - symmetric system 

      Kartashov, Yaroslav V.; Milian, Carles; Konotop, Vladimir V; Torner Sabata, Lluís (2018-02-01)
      Article
      Open Access
      We address a 2D parity-time (¿¿)-symmetric structure built as a chain of waveguides, where all waveguides except for the central one are conservative, while the central one is divided into two halves with gain and losses. ...
    • Broad area lasers beam quality improvement using photonic crystals 

      Garre Werner, Guillermo (Universitat Politècnica de Catalunya, 2017-10-27)
      Master thesis
      120 months embargo
      Edge-emitting broad area semiconductor lasers (BAL) have a wide range of applications due to their high power, however, are strongly limited by their beam quality. Here, we consider a BAL with an external cavity configuration ...
    • Carbon Dioxide optical detection by macroporous silicon 

      Vega, Didac; Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel (2014)
      Conference report
      Restricted access - publisher's policy
    • Characterization of 2D macroporous silicon photonic crystals: improving the photonic band identification in angular-dependent reflection spectroscopy in the mid-IR 

      Král, Z; Ferré Burrull, José; Pallarès Marzal, Josep; Todorov Trifonov, Trifon; Rodríguez Martínez, Ángel; Alcubilla González, Ramón; Marsal, L F (2008-02)
      Article
      Restricted access - publisher's policy
      We report the experimental characterization of two-dimensional (2D) macroporous silicon photonic crystals using angular-dependent reflectance spectroscopy in the mid-IR region. We have investigated different sample structures ...
    • 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 ...
    • 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 ...
    • Enhancing light harvesting in organic photovoltaics by photonic nanostructures 

      Gibert Roca, Martí (Universitat Politècnica de Catalunya, 2017-07-09)
      Master thesis
      Open Access
      Organic solar cells have become a suitable photovoltaic technology thanks to their flexibility, scalability and light weight layout. They offer many advantages over the prevalent silicon industry, however, their efficiency ...