Now showing items 1-20 of 59

    • Absorption enhancement of molecules in the weak plasmon-exciton coupling regime 

      Balci, S.; Karademir, E.; Kocabas, C.; Aydınlı, Atilla (Optical Society of American (OSA), 2014)
      We report on the experimental and theoretical investigations of enhancing the optical absorption of organic molecules in the weak plasmon-exciton coupling regime. A metal-organic hybrid structure consisting of dye molecules ...
    • Anharmonicity of zone-center optical phonons: Raman scattering spectra of GaSe0.5S0.5 layered crystal 

      Gasanly, N. M.; Aydınlı, Atilla; Kocabas, C.; Özkan H. (IOPscience, 2002)
      The temperature dependencies (10-300 K) of the eight Raman-active mode frequencies and linewidths in GaSe0.5S0.5 layered crystal have been measured in the frequency range from 10 to 320 cm-1. We observed softening and ...
    • Broadband optical modulators based on graphene supercapacitors 

      Polat, E. O.; Kocabas, C. (American Chemical Society, 2013)
      Optical modulators are commonly used in communication and information technology to control intensity, phase, or polarization of light. Electro-optic, electroabsorption, and acousto-optic modulators based on semiconductors ...
    • Broadband terahertz modulators using self-gated graphene capacitors 

      Kakenov, N.; Balci, O.; Polat, E. O.; Altan, H.; Kocabas, C. (Optical Society of America, 2015)
      We demonstrate a terahertz intensity modulator using a graphene supercapacitor which consists of two large-area graphene electrodes and an electrolyte medium. The mutual electrolyte gating between the graphene electrodes ...
    • Comparison of back and top gating schemes with tunable graphene fractal metasurfaces 

      Aygar, A. M.; Balci, O.; Cakmakyapan, S.; Kocabas, C.; Caglayan, H.; Özbay, Ekmel (American Chemical Society, 2016)
      In this work, fractal metasurfaces that consist of periodic gold squares on graphene are used to increase light-graphene interaction. We show by simulations and experiments that higher level fractal structures result in ...
    • Critical coupling in plasmonic resonator arrays 

      Balci, S.; Kocabas, C.; Aydınlı, Atilla (Optical Society of America, 2011)
      We report critical coupling of electromagnetic waves to plasmonic cavity arrays fabricated on Moire surfaces. Dark field plasmon microscopy imaging and polarization dependent spectroscopic reflection measurements reveal ...
    • Design and analysis of integrated optical sensors for scanning probe microscopies 

      Kocabas, C.; Aydınlı, Atilla (IEEE, 2005)
      In this paper, a novel probe for displacement sensing will be introduced. It is based on a conventional GaAs cantilever, integrated with a Bragg grating as a photo-elastic strain sensor. The deflection of the cantilever ...
    • Dynamic tuning of plasmon resonance in the visible using graphene 

      Balci, S.; Balci, O.; Kakenov, N.; Atar, F. B.; Kocabas, C. (The Optical Society, 2016)
      We report active electrical tuning of plasmon resonance of silver nanoprisms (Ag NPs) in the visible spectrum. Ag NPs are placed in close proximity to graphene which leads to additional tunable loss for the plasmon resonance. ...
    • Enhanced tunability of V-shaped plasmonic structures using ionic liquid gating and graphene 

      Ozdemir, O.; Aygar, A. M.; Balci, O.; Kocabas, C.; Caglayan, H.; Özbay, Ekmel (Elsevier Ltd, 2016)
      Graphene is a strong candidate for active optoelectronic devices because of its electrostatically tunable optical response. Current substrate back-gating methods are unable to sustain high fields through graphene unless a ...
    • Experimental and theoretical studies of transport through large scale, partially aligned arrays of single-walled carbon nanotubes in thin film type transistors 

      Kocabas, C.; Pimparkar, N.; Yesilyurt O.; Kang, S.J.; Alam, M.A.; Rogers J.A. (2007)
      Gate-modulated transport through partially aligned films of single-walled carbon nanotubes (SWNTs) in thin film type transistor structures are studied experimentally and theoretically. Measurements are reported on SWNTs ...
    • Femtosecond pulse generation with voltage-controlled graphene saturable absorber 

      Baylam, M. N.; Cizmeciyan, S.; Ozharar, S.; Polat, E. O.; Kocabas, C.; Sennaroglu, A. (Optical Society of America, 2014)
      We report, for the first time to our knowledge, the demonstration of a graphene supercapacitor as a voltage-controlled saturable absorber for femtosecond pulse generation from a solid-state laser. By applying only a few ...
    • Gate-tunable photoemission from graphene transistors 

      Copuroglu, M.; Aydogan, P.; Polat, E. O.; Kocabas, C.; Süzer, S. (American Chemical Society, 2014)
      In this Letter, we report gate-tunable X-ray photoelectron emission from back-gated graphene transistors. The back-gated transistor geometry allows us to study photoemission from graphene layer and the dielectric substrate ...
    • Generation of Sub-20-fs Pulses From a Graphene Mode-Locked Laser 

      Canbaz, F.; Kakenov, N.; Kocabas, C.; Demirbas, U.; Sennaroglu, A. (OSA - The Optical Society, 2017)
      We demonstrate, what is to our knowledge, the shortest pulses directly generated to date from a solid-state laser, mode locked with a graphene saturable absorber (GSA). In the experiments, a low-threshold diode-pumped ...
    • Graphene as a Reversible and Spectrally Selective Fluorescence Quencher 

      Salihoglu, O.; Kakenov, N.; Balci, O.; Balci, S.; Kocabas, C. (Nature Publishing Group, 2016)
      We report reversible and spectrally selective fluorescence quenching of quantum dots (QDs) placed in close proximity to graphene. Controlling interband electronic transitions of graphene via electrostatic gating greatly ...
    • Graphene based flexible electrochromic devices 

      Polat, E. O.; Balci, O.; Kocabas, C. (Nature Publishing Group, 2014-10-01)
      Graphene emerges as a viable material for optoelectronics because of its broad optical response and gate-tunable properties. For practical applications, however, single layer graphene has performance limits due to its small ...
    • Graphene based terahertz phase modulators 

      Kakenov, N.; Ergoktas, M. S.; Balci, O.; Kocabas, C. (IOP Publishing, 2018)
      Electrical control of amplitude and phase of terahertz radiation (THz) is the key technological challenge for high resolution and noninvasive THz imaging. The lack of active materials and devices hinders the realization ...
    • Graphene mode-locked Cr:LiSAF laser at 850 nm 

      Canbaz F.; Kakenov, N.; Kocabas, C.; Demirbas, U.; Sennaroglu, A. (OSA - The Optical Society, 2015)
      We report, for the first time to our knowledge, a mode-locked femtosecond Cr:LiSAF laser initiated with a high-quality monolayer graphene saturable absorber (GSA), synthesized by chemical-vapor deposition. The tight-focusing ...
    • Graphene mode-locked femtosecond Alexandrite laser 

      Cihan, C.; Kocabas, C.; Demirbas U.; Sennaroglu, A. (OSA - The Optical Society, 2018)
      We report for the first time, to the best of our knowledge, graphene mode-locked operation of a femtosecond Alexandrite laser at 750 nm. A multipass-cavity configuration was employed to scale the output energy and to ...
    • Graphene mode-locked femtosecond Cr: LiSAF laser 

      Canbaz F.; Kakenov, N.; Kocabas, C.; Demirbas, U.; Sennaroglu, A. (Optical Society of America (OSA), 2015)
      We report the first demonstration of femtosecond pulse generation from a Cr:LiSAF laser mode-locked with a monolayer graphene saturable absorber. Nearly transform-limited 72-fs pulses were generated at 850 nm with only two ...
    • Graphene mode-locked multipass-cavity femtosecond Cr4+:forsterite laser 

      Ozharar, S.; Baylam, I.; Cizmeciyan, M. N.; Balci, O.; Pince, E.; Kocabas, C.; Sennaroglu, A. (Optical Society of America, 2013-04-19)
      We report, for the first time to our knowledge, the use of graphene as a saturable absorber in an energy-scaled femtosecond Cr4+: forsterite laser. By incorporating a multipass cavity, the repetition rate of the original ...