Now showing items 1-13 of 13

    • Actively tunable thin films for visible light by thermo-optic modulation of ZnO 

      Battal, E.; Okyay, A., K. (Wiley-VCH Verlag, 2016)
      Applications of active control of light matter interactions within integrated photonics, hyper-spectral imaging, reconfigurable lasers, and selective bio-surfaces have enormously increased the demand for realization of ...
    • Blue InGaN/GaN-based quantum electroabsorption modulators 

      Sarı, Emre; Nizamoğlu, Sedat.; Özel, Tuncay; Demir, Hilmi Volkan (IEEE, 2006)
      We introduce InGaN/GaN-based quantum electroabsorption modulator that incorporates ∼5 nm thick In0.35Ga0.65N/GaN quantum structures for operation in the blue spectral range of 420-430 nm. This device exhibits an optical ...
    • 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 ...
    • Broadband THz modulators based on multilayer graphene on PVC 

      Kaya E.; Kakenov N.; Kocabas C.; Altan H.; Esenturk O. (IEEE Computer Society, 2016)
      In this study we present the direct terahertz time-domain spectroscopic measurement of CVD-grown multilayer graphene (MLG) on PVC substrate with an electrically tunable Fermi level. In a configuration consisting MLG and ...
    • Compact optical temporal processors 

      Mendlovic, D.; Melamed, O.; Ozaktas, H. M. (Optical Society of America, 1995)
      Optical signal processing can be done with time-lens devices. A temporal processor based on chirp-z transformers is suggested. This configuration is more compact than a conventional 4-f temporal processor. On the basis of ...
    • Electrically controlled terahertz spatial light modulators with graphene arrays 

      Kakenov, N.; Takan, T.; Ozkan, V. A.; Balci, O.; Polat, E. O.; Altan, H.; Kocabas, C. (Institute of Electrical and Electronics Engineers Inc., 2016)
      Gate-tunable high-mobility electrons on atomically thin graphene layers provide a unique opportunity to control electromagnetic waves in a very broad spectrum. In this paper, we describe an electrically-controlled multipixel ...
    • Electrically-reconfigurable integrated photonic switches 

      Fidaner, O.; Demir, Hilmi Volkan; Sabnis V.A.; Harris Jr. J.S.; Miller, D.A.B.; Zheng J.-F. (IEEE, 2004)
      We report remotely electrically reconfigurable photonic switches that intimately integrate waveguide electroabsorption modulators with surface-normal photodiodes, avoiding conventional electronics. These switches exhibit ...
    • 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 ...
    • Femtosecond Yb-doped fiber laser system at 1 μm of wavelength with 100-nm bandwidth and variable pulse structure for accelerator diagnostics 

      Winter, A.; Ilday, F. Ö.; Steffen, B. (2007)
      Laser-based diagnostic systems play an increasingly important role in accelerator diagnostics in, for instance, electron bunch length measurements. To date, the laser system of choice for electro-optic experiments has been ...
    • A hole modulator for InGaN/GaN light-emitting diodes 

      Zhang, Z-H.; Kyaw, Z.; Liu W.; Ji Y.; Wang, L.; Tan S.T.; Sun, X. W.; Demir, H. V. (American Institute of Physics, 2015)
      The low p-type doping efficiency of the p-GaN layer has severely limited the performance of InGaN/GaN light-emitting diodes (LEDs) due to the ineffective hole injection into the InGaN/GaN multiple quantum well (MQW) active ...
    • Lyotropic liquid-crystalline mesophase of lithium triflate-nonionic surfactant as gel electrolyte for graphene optical modulator 

      Balci, F. M.; Balci, S.; Kocabas, C.; Dag, Ö. (American Chemical Society, 2017)
      Lithium salt (noncoordinating anions, such as lithium triflate (Ltf)) gel electrolytes may be key for the practical use of electrochemical devices. We introduce a new lyotropic liquid-crystalline (LLC) mesophase using Ltf, ...
    • Multifunctional integrated photonic switches 

      Demir, H. M.; Sabnis, V. A.; Fidaner, O.; Zheng, J.-F.; Harris, J. S.; Miller, D. A. B. (Institute of Electrical and Electronics Engineers, 2005)
      Traditional optical-electronic-optical (o-e-o) conversion in today’s optical networks requires cascading separately packaged electronic and optoelectronic chips and propagating high-speed electrical signals through and ...
    • Photonic devices and systems embedded with nanocyrstals 

      Demir, Hilmi Volkan; Soğancı, Ibrahim Murat; Mutlugun, Evren; Tek, Sümeyra; Huyal, Ilkem Ozge (2006)
      We review our research work on the development of photonic devices and systems embedded with nanocyrstals for new functionality within EU Phoremost Network of Excellence on nanophotonics. Here we report on CdSe/ZnS ...