Browsing by Author "Caglayan, H."

Now showing items 21-40 of 46

    • Frequency dependent steering with backward leaky waves via photonic crystal interface layer 

      Colak, E.; Caglayan, H.; Cakmak, A. O.; Villa, A. D.; Capolino, F.; Özbay, Ekmel (Optical Society of America, 2009)
      A Photonic Crystal (PC) with a surface defect layer (made of dimers) is studied in the microwave regime. The dispersion diagram is obtained with the Plane Wave Expansion Method. The dispersion diagram reveals that the ...

    • Generation of an axially asymmetric bessel-like beam from a metallic subwavelength aperture 

      Li, Z.; Alici, K. B.; Caglayan, H.; Özbay, Ekmel (American Physical Society, 2009)
      An electromagnetic nondiffractive Bessel-like beam from a subwavelength aperture is generated by placing a metallic circular gratinglike structure in front of the aperture. When the incident wave is linearly polarized, the ...

    • Graphene-based tunable plasmon induced transparency in gold strips 

      Habib, M.; Rashed, A. R.; Özbay, Ekmel; Caglayan, H. (Optical Society of America, 2018)
      Plasmon induced transparency (PIT) has been numerically investigated and experimentally realized by two parallel gold strips on graphene for the mid-infrared (MIR) range. The PIT response is realized by the weak hybridization ...

    • 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 ...

    • High efficiency of graded index photonic crystal as an input coupler 

      Cakmak, A. O.; Colak, E.; Caglayan, H.; Kurt, H.; Özbay, Ekmel (AIP Publishing LLC, 2009)
      A graded index photonic crystal (GRIN PC) configuration was placed at the input side of a photonic crystal waveguide (PCW) in order to efficiently couple the light waves into the waveguide. We compared the transmission ...

    • Highly directional enhanced radiation from sources embedded inside three-dimensional photonic crystals 

      Caglayan, H.; Bulu, I.; Özbay, Ekmel (Optical Society of America, 2005)
      We have experimentally studied emission of microwave radiation from a monopole source embedded in a three-dimensional photonic crystal. We have demonstrated enhancement of microwave radiation at the band edge and cavity ...

    • Highly directive radiation from sources embedded inside photonic crystals 

      Bulu, I.; Caglayan, H.; Özbay, Ekmel (American Institute of Physics, 2003)
      In this work, we have experimentally and theoretically studied the angular distribution of power emitted from a radiation source embedded inside a photonic crystal. Our results show that it is possible to obtain highly ...

    • Highly-sensitive refractive index sensing by near-infrared metatronic nanocircuits 

      Rashed, A. R.; Gudulluoglu, B.; Yun, H. W.; Habib, M.; Boyaci, I. H.; Hong, S. H.; Özbay, Ekmel; Caglayan, H. (Nature Publishing Group, 2018)
      In this work, we present a highly-sensitive refractive index sensor based on metatronic nanocircuits operating at near-infrared spectral range. The structure is designed based on simple nanorod geometry and fabricated by ...

    • 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 ...

    • Multiple slow waves and relevant transverse transmission and confinement in chirped photonic crystals 

      Serebryannikov, A. E.; Cakmak, A. O.; Colak, E.; Caglayan, H.; Kurt, H.; Özbay, Ekmel (OSA Publishing, 2014-09-02)
      The dispersion properties of rod-type chirped photonic crystals (PhCs) and non-channeled transmission in the direction of the variation of structural parameters from one cell of such a PhC to another are studied. Two types ...

    • Negative refraction and focusing of electromagnetic waves by metallodielectric photonic crystals 

      Bulu, I.; Caglayan, H.; Özbay, Ekmel (American Physical Society, 2005)
      In this work, we have experimentally and theoretically studied negative refraction of electromagnetic waves by a metallodielectric photonic crystal. We showed that by adding a periodic dielectric perturbation to the unit ...

    • Observation of cavity structures in composite metamaterials 

      Caglayan, H.; Özbay, Ekmel (S P I E - International Society for Optical Engineering, 2010-07-29)
      We investigated the cavity structure by the deformation of a unit cell of a Composite Metamaterial (CMM) structure. We considered different cavity structures with different resonance frequencies and Q-factors. We observed ...

    • Observation of coupled-cavity structures in metamaterials 

      Caglayan, H.; Bulu, I.; Loncar, M.; Özbay, Ekmel (AIP Publishing LLC, 2008)
      In this letter, we investigated the transmission properties of metamaterial based coupled-cavity structures. We first calculated the effective parameters of a split-ring resonator (SRR) and composite metamaterial (CMM) ...

    • Observation of negative refraction and focusing in two-dimensional photonic crystals 

      Özbay, Ekmel; Bulu, M.; Guven, K.; Caglayan, H.; Aydin, K. (Institute of Physics Publishing Ltd., 2006)
      We experimentally and theoretically demonstrate the negative refraction and focusing of electromagnetic (EM) waves by twodimensional photonic crystal slabs at microwave frequencies. The negative refraction is observed both ...

    • Observation of off-axis directional beaming via subwavelength asymmetric metallic gratings 

      Caglayan, H.; Bulu, I.; Özbay, Ekmel (Institute of Physics Publishing Ltd., 2009)
      It is possible to obtain enhanced and directional beams using subwavelength metallic structures. However, the enhanced beams throughout such structures are only directed towards the propagation direction. In this study, ...

    • Off-axis beaming from subwavelength apertures 

      Caglayan, H.; Bulu, I.; Özbay, Ekmel (AIP Publishing LLC, 2008)
      Photonic crystal waveguides and metallic subwavelength apertures are promising tools for light manipulation. It is possible to obtain enhanced directional beams by using these structures via coupling to surface waves. In ...

    • Off-axis directional beaming via photonic crystal surface modes 

      Caglayan, H.; Bulu, I.; Özbay, Ekmel (AIP Publishing LLC, 2008-03-07)
      We investigated off-axis directional beaming from a photonic crystal (PC) waveguide. We theoretically and experimentally demonstrated that it is possible to control beaming from a PC waveguide via PC surface modes using a ...

    • 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 ...

    • Radiation properties of sources inside photonic crystals 

      Bulu, I.; Caglayan, H.; Özbay, Ekmel (2003)
      In this work, we have experimentally studied the emission of radiation from a monopole source embedded in a photonic crystal. We have demonstrated the enhancement of radiation at the band edges and at the cavity modes ...

    • Study of the field emitted by a source placed inside a two-dimensional left-handed metamaterial 

      Bulu, I.; Caglayan, H.; Aydin, K.; Özbay, Ekmel (Optical Society of America, 2007)
      We studied the properties of electromagnetic waves that were emitted from a source placed inside a left-handed medium based on a two-dimensional labyrinth. While the arguments of geometrical optics suggest that the field ...