Now showing items 1-12 of 12

    • Band-gap renormalization in quantum wires 

      Güven, Kaan; Bennett, C.R.; Tanatar, Bilal (TÜBİTAK, 1999)
      Improved techniques in semiconductor fabrication increased the interest in quantum wire structures, because of their opto-electronic device application possibilities. Many-body interactions among the electrons and holes ...
    • Experimental analysis of true left-handed behaviour and transmission properties of composite metamaterials 

      Güven, Kaan; Aydın, Koray; Özbay, Ekmel (Elsevier, 2005-12)
      We report the true left-handed transmission of a composite metamaterial (CMM) consisting of periodically stacked split-ring resonator (SRR) and wire elements. The negative permeability (μ < 0) gap is demonstrated explicitly ...
    • Experimental observation of true left-handed metamaterial 

      Aydın, Koray; Güven, Kaan; Özbay, Ekmel (IEEE, 2005)
      We report a true left-handed (LH) behavior in composite metamaterials. The magnetic resonance of the SRR structure is demonstrated. Plasma frequency of the LH material is shown to be lower than that of the wires.
    • Many-body interaction effects in quasi-one-dimensional photo-excited electron-hole systems 

      Güven, Kaan (Bilkent University, 1999)
      The work in this thesis concerns rnany-body interaction effects in a quasi-onedimensional electron-hole plasma, which may be generated under intense photoexcitation in a semiconductor quantum-well wire. In particular, ...
    • Near-field measurement of a planar meta-surface illuminated by dipole antennas 

      Saenz, E.; Güven, Kaan; Ederra, I.; Özbay, Ekmel; De Maagt, P.; Gonzalo, R. (IEEE, 2008-03)
      In this paper, the uniform illumination of a meta-surface that is fed by a single dipole antenna or an array is experimentally investigated by means of near-field measurements. The results of the scanned field, when the ...
    • Negative refraction and subwavelength focusing using photonic crystals 

      Özbay, Ekmel; Aydın, Koray; Alıcı, Kamil Boratay; Güven, Kaan (SPIE, 2005-01)
      We review certain novel optical properties of two-dimensional dielectric photonic crystals (PCs) which exhibit negative refraction behavior. We investigate two mechanisms which utilize the band structure of the PC and lead ...
    • Phonon renormalization effects in low dimensional electron-hole systems 

      Güven, Kaan (Bilkent University, 1995)
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    • Physics and applications of defect structures in photonic crystals 

      Özbay, Ekmel; Güven, Kaan; Bayındır, Mehmet (SPIE, 2003)
      Photonic crystals are three dimensional periodic structures having the property of reflecting the electromagnetic (EM) waves in all dimensions, for a certain range of frequencies. Defects or cavities around the same geometry ...
    • Physics and applications of photonic nanocrystals 

      Özbay, Ekmel; Güven, Kaan; Aydın, Koray; Bayındır, Mehmet (Inderscience Publishers, 2004)
      Photonic nanocrystals are periodic dielectric or metallic structures having photonic bands in analogy to electronic bands of semiconductors. The presence of photonic band-gaps, where the propagation of photons of certain ...
    • Plasmon-LO-phonon coupling effects on the drag rate in double quantum-well systems 

      Güven, Kaan; Tanatar, Bilal (Elsevier, 1997)
      We study the Coulomb drag rate for electrons in a double-quantum-well structure taking into account the electron-optical phonon interactions. The full wave vector and frequency dependent random-phase approximation (RPA) ...
    • Spectral negative refraction and focusing analysis of a two-dimensional left-handed photonic crystal lens 

      Güven, Kaan; Aydın, Koray; Alıcı, Kamil Boratay; Soukoulis, C. M.; Özbay, Ekmel (American Physical Society, 2004-11)
      We report the spectral refraction analysis and focusing properties of a two-dimensional, dielectric photonic crystal (PC) slab in freespace. A transverse electric polarized upper band of the crystal is used. The measured ...
    • Two-dimensional left-handed metamaterial with a negative refractive index 

      Aydın, Koray; Güven, Kaan; Özbay, Ekmel (IOP, 2006)
      We present a two-dimensional metamaterial with left-handed properties in a certain frequency range where both effective dielectric permittivity and magnetic permeability is simultaneously negative. A wedge-shaped metamaterial ...