Now showing items 1-18 of 18

    • Broadband absorption enhancement in an uncooled microbolometer infrared detector 

      Kebapcı, B.; Dervişoğlu, Ö.; Battal, Enes; Okyay, Ali Kemal; Akın, T. (SPIE, 2014)
      This paper introduces a method for a broadband absorption enhancement in the LWIR range (8-12 μm), in single layer microbolometer pixels with 35 μm pitch. For the first time in the literature, this study introduces a very ...
    • Concentric ring structures as efficient SERS substrates 

      Cinel, N. A.; Cakmakyapan, S.; Ertas, G.; Özbay, Ekmel (Institute of Electrical and Electronics Engineers, 2013)
      Plasmonic nanopatterned structures that can work as highly efficient surface-enhanced Raman scattering (SERS) substrates are presented in this study. A 'coupled' concentric ring structure has been designed, fabricated, ...
    • Coupled plasmonic structures for sensing, energy and spectroscopy applications 

      Ayas, Sencer (Bilkent University, 2015-08)
      Recent advances in nanofabrication and characterization methods have enabled the study of novel optical phenomena, thus boosting the research in nanophotonics and plasmonics. Metal nanostructures offer a route for the ...
    • Enhanced optical characteristics of light emitting diodes by surface plasmon of Ag nanostructures 

      Jang L.-W.; Ju J.-W.; Jeon J.-W.; Jeon, D.-W.; Choi J.-H.; Lee, S.-J.; Jeon, S.-R.; Baek J.-H.; Sarı, Emre; Demir, Hilmi Volkan; Yoon H.-D.; Hwang, S.-M.; Lee I.-H. (SPIE, 2011)
      We investigated the surface plasmon coupling behavior in InGaN/GaN multiple quantum wells at 460 nm by employing Ag nanostructures on the top of a roughened p-type GaN. After the growth of a blue light emitting diode ...
    • Experimental validation of strong directional selectivity in nonsymmetric metallic gratings with a subwavelength slit 

      Cakmakyapan, S.; Caglayan, H.; Serebryannikov, A. E.; Özbay, Ekmel (American Institute of Physics, 2011-02-02)
      Strong directional selectivity is theoretically predicted and experimentally validated at the microwave frequencies in the beaming regime for a single subwavelength slit in nonsymmetric metallic gratings with double-side ...
    • Guided plasmon modes of a graphene-coated kerr slab 

      Hajian, H.; Rukhlenko, I. D.; Leung, P. T.; Caglayan, H.; Özbay, Ekmel (Springer New York LLC, 2016)
      We study analytically propagating surface plasmon modes of a Kerr slab sandwiched between two graphene layers. We show that some of the modes that propagate forward at low field intensities start propagating with negative ...
    • Hybridization of fano and vibrational resonances in surface-enhanced infrared absorption spectroscopy of streptavidin monolayers on metamaterial substrates 

      Alici, K. B. (2014)
      We present spectral hybridization of organic and inorganic resonant materials and related bio-sensing mechanism. We utilized a bound protein (streptavidin) and a Fano-resonant metasurface to illustrate the concept. The ...
    • Long-range tamm surface plasmons supported by graphene-dielectric metamaterials 

      Hajian, H.; Caglayan, H.; Özbay, Ekmel (American Institute of Physics Inc., 2017)
      Considering the Ohmic losses of graphene in the calculations and by obtaining exact dispersion relations of the modes, we theoretically study propagation and localization characteristics of Tamm surface plasmons supported ...
    • Metal-semiconductor-metal UV photodetector based on Ga doped ZnO/graphene interface 

      Kumar, M.; Noh, Y.; Polat, K.; Okyay, Ali Kemal; Lee, D. (Pergamon Press, 2015)
      Fabrication and characterization of metal-semiconductor-metal (MSM) ultraviolet (UV) photodetector (PD) based on Ga doped ZnO (ZnO:Ga)/graphene is presented in this work. A low dark current of 8.68 nA was demonstrated at ...
    • Nearly perfect resonant absorption and coherent thermal emission by hBN-based photonic crystals 

      Hajian, H.; Ghobadi, A.; Butun, B.; Özbay, Ekmel (Optical Society of America, 2017)
      In this paper, we numerically demonstrate mid-IR nearly perfect resonant absorption and coherent thermal emission for both polarizations and wide angular region using multilayer designs of unpatterned films of hexagonal ...
    • One-way transmission through the subwavelength slit in nonsymmetric metallic gratings 

      Cakmakyapan, S.; Serebryannikov, A. E.; Caglayan, H.; Özbay, Ekmel (Optical Society of America, 2010-07-27)
      An approach for obtaining one-way transmission in the beaming regime is suggested that is based on the directional radiation of surface plasmons in nonsymmetric metallic gratings with a single slit. In contrast to the ...
    • A plasmonically enhanced pixel structure for uncooled microbolometer detectors 

      Erturk O.; Battal, Enes; Kucuk, S.E.; Okyay, Ali Kemal; Akin, T. (SPIE, 2013)
      This paper introduces a method of broadband absorption enhancement that can be integrated with the conventional suspended microbolometer process with no significant additional cost. The premise of this study is that electric ...
    • Semiconductor-less photovoltaic device 

      Atar, Fatih B.; Battal, Enes; Aygun, Levent E.; Dağlar, Bihter; Bayındır, Mehmet; Okyay, Ali Kemal (IEEE, 2013)
      We demonstrate a novel semiconductor-less photovoltaic device and investigate the plasmonic effects on this device structure. The device is made of metal and dielectric layers and the operation is based on hot carrier ...
    • Slowing down surface plasmons on a Moiré surface 

      Kocabaş, Aşkın; Şenlik, S. Seçkin; Aydınlı, Atilla (The American Physical Society, 2009-02)
      We have demonstrated slow propagation of surface plasmons on metallic Moiré surfaces. The phase shift at the node of the Moiré surface localizes the propagating surface plasmons and adjacent nodes form weakly coupled ...
    • Spoof-plasmon relevant one-way collimation and multiplexing at beaming from a slit in metallic grating 

      Çakmakyapan, Semih; Serebryannikov, A.E.; Caglayan H.; Özbay, Ekmel (Optical Society of America, 2012)
      Diode and collimator/multiplexer functions are suggested to be combined in one device that is based on a thin metallic grating with a single subwavelength slit. A proper choice of the structural (a)symmetry of the grating ...
    • Tunable graphene plasmonic structures with different gating schemes 

      Aygar, Ayşe Melis (Bilkent University, 2016-08)
      The aim of this thesis is to examine graphene plasmonic structures which yields actively tunable spectral resonances and compare two different ways to gate graphene. Plasmonic structures that consist of periodic fractal ...
    • Tuning optical discs for plasmonic applications 

      Kaplan, B.; Guner, H.; Senlik, O.; Gurel, K.; Bayındır, Mehmet; Dana, A. (Springer New York, 2009)
      We present simple physical and chemical procedures that allow tuning and modification of the topography of gratings present in optical storage discs into geometries optimal for grating coupled plasmon resonance excitation. ...
    • Ultrahigh contrast one-way optical transmission through a subwavelength slit 

      Battal, E.; Yogurt, T. A.; Okyay, Ali Kemal (Springer, 2013)
      We computationally demonstrate one-way optical transmission characteristics of a subwavelength slit. We comparatively study the effect in single layer and double layer metallic corrugations. We also investigate the effect ...