Browsing by Keywords "Photonic crystals"

Now showing items 21-40 of 42

    • 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 ...

    • One and two dimensional LiNbO3 photonic crystals 

      Şimşek, Şevket; Mamedov, Amirullah M.; Özbay, Ekmel (IEEE, 2013)
      In this report, we present an investigation of the optical properties and band structure calculations for the photonic crystal structures (PCs) based on one-dimensional (1D) and two-dimensional (2D) ferroelectric LiNbO3 ...

    • Optical bistability in one-dimensional doped photonic crystals with spontaneously generated coherence 

      Aas, S.; Müstecaplioǧlu O.E. (2013)
      We investigate optical bistability in a multilayer one-dimensional photonic crystal where the central layer is doped with Λ-type three-level atoms. We take into account the influence of spontaneously generated coherence ...

    • Photonic band gaps with layer-by-layer double-etched structures 

      Biswas, R.; Özbay, Ekmel; Ho, K. M. (A I P Publishing LLC, 1996-09-03)
      Periodic layer‐by‐layer dielectric structures with full three‐dimensional photonic band gaps have been designed and fabricated. In contrast to previous layer‐by‐layer structures the rods in each successive layer are at an ...

    • Photonic crystal based multi-mode high-qcavity 

      Akosman, Ahmet Emin; Mutlu, Mehmet; Kurt H.; Özbay, Ekmel (IEEE, 2011)
      An optical race-track has been investigated in order to obtain a multi resonant structure with high-Q factors. Photonic crystal based structure provides strong field confinement and scalability in the dimensions of the ...

    • Photonic Crystal based spatial filtering 

      Colak, E.; Çakmak, A. Özgür; Serebryannikov, Andriy E.; Özbay, Ekmel (IEEE, 2009)
      Two dimensional Photonic Crystal structure is used to achieve spatial filtering. The structure provides bandstop filtering in the incident angle range of 18° to 38°. The transmission is close to unity outside of this range. ...

    • Photonic-crystal-based resonant-cavity-enhanced detectors 

      Temelkuran, Burak; Özbay, Ekmel; Kavanaugh, J. P.; Tuttle, G.; Ho, K. M. (IEEE, 1998)
      A layer-by-layer three-dimensional photonic crystal, with a full photonic bandgap (PBG) in all directions is proposed. The electrical fields in the cavities of this crystal are usually enhanced, and by placing active devices ...

    • 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 crystals 

      Özbay, Ekmel; Bulu I.; Aydin, K.; Caglayan H.; Guven, K. (Nanotechnology Research Center NANOTAM, 2004)
      In this article, we investigate how the photonic band gaps and the variety of band dispersions of photonic crystals can be utilized for various applications and how they further give rise to completely novel optical ...

    • Properties of a microjoule-class fiber oscillator mode-locked with a SESAM 

      Lecaplain, C.; Ortac, Bülend; MacHinet G.; Boullet J.; Baumgartl, M.; Schreiber, T.; Cormier, E.; Hideur, A. (IEEE, 2011)
      Energy scaling of ultrafast Yb-doped fiber oscillators has experienced rapid progress largely driven by many applications that require high average power femtosecond pulses. The fundamental challenge for ultrafast fiber ...

    • Reflection properties and defect formation in metallic photonic crystals 

      Özbay, Ekmel; Temelkuran, Burak; Sigalas, M.; Tuttle, G.; Soukoulis, C. M.; Ho, K. M. (IEEE, 1998-05)
      The reflection properties of layer-by-layer metallic photonic crystals were investigated using metallic photonic crystals with simple-tetragonal (st) structure. The observed properties were used to predict defect formation ...

    • Reflection properties and defect formation in photonic crystals 

      Özbay, Ekmel; Temelkuran, B. (A I P Publishing LLC, 1996-08-05)
      We have investigated the surface reflection properties of a layer-by-layer photonic crystal. By using a Fabry-Perot resonant cavity analogy along with the reflection-phase information of the photonic crystal, we predicted ...

    • Refractive index-enhanced vortex lattices 

      Müstecaplıoǧlu, Ö. E.; Öktel, M. Özgür (SPIE, 2005)
      Light propagation through vortex matter in atomic Bose-Einstein condensates is examined. It is shown that vortex matter can be used as a photonic crystal by a refractive index enhancement scheme. Band structure of the ...

    • Resonant cavity-enhanced detectors embedded in photonic crystals 

      Temelkuran, Burak; Özbay, Ekmel (IEEE, 1996)
      Summary form only given. We demonstrate the resonant-cavity-enhanced effect by placing microwave detectors in a layer-by-layer photonic crystal. We used the output of a network analyzer as the microwave source, and fed the ...

    • Spatial filtering using dielectric photonic crystals at beam-type excitation 

      Colak, E.; Cakmak, A. O.; Serebryannikov, A. E.; Özbay, Ekmel (American Institute of Physics, 2010-12-06)
      Spatial filtering is demonstrated at beam-type excitations by utilizing finite thickness slabs of two-dimensional dielectric photonic crystals (PCs) showing exotic Fabry-Perot resonances that are preserved over a wide range ...

    • Strong enhancement of spontaneous emission in amorphous-silicon-nitride photonic crystal based coupled-microcavity structures 

      Bayındır, Mehmet; Tanriseven, S.; Aydınlı, Atilla; Özbay, Ekmel (Wiley, 2001)
      We investigated photoluminescence (PL) from one-dimensional photonic band gap structures. The photonic crystals, a Fabry-Perot (FP) resonator and a coupled-microcavity (CMC) structure, were fabricated by using alternating ...

    • Sub-picosecond microjoule-class fiber lasers 

      Lecaplain, C.; Ortaç, Bülend; MacHinet G.; Boullet J.; Baumgartl, M.; Schreiber, T.; Cormier, E.; Hideur, A. (Optical Society of America, 2011)
      We study the impact of the mode-locking mechanism on the performances of a microjoule-class all-normal dispersion fiber laser featuring large-mode-area photonic crystal fibers. © 2011 OSA.

    • Tight-binding mechanism in slow light regime 

      Akosman, Ahmet Emin; Mutlu, Mehmet; Kurt, Hamza; Özbay, Ekmel (IEEE, 2011)
      In this study, tight-binding formalism is applied to a photonic crystal coupled cavity structure in order to investigate the characteristics of ultra slow light modes. Eigen-mode splitting is observed and resulting group ...

    • Tunable zero-index photonic crystal waveguide for two-qubit entanglement detection 

      Özgün E.; Özbay, Ekmel; Caglayan, H. (American Chemical Society, 2016)
      Preparation and measurement of an entangled state are essential in quantum information applications. The recent theoretical works on preparing and measuring entangled states via coupled quantum dot-waveguide platforms are ...

    • Unidirectional transmission in photonic-crystal gratings at beam-type illumination 

      Cakmak, A.O.; Colak, E.; Serebryannikov, A.E.; Özbay, Ekmel (Optical Society of American (OSA), 2010)
      Unidirectional transmission is studied theoretically and experimentally for the gratings with one-side corrugations (non-symmetric gratings), which are based on two-dimensional photonic crystals composed of alumina rods. ...