Now showing items 1-20 of 39

    • 2D material liquid crystals for optoelectronics and photonics 

      Hogan B.T.; Kovalska E.; Craciun M.F.; Baldycheva A. (Royal Society of Chemistry, 2017)
      The merging of the materials science paradigms of liquid crystals and 2D materials promises superb new opportunities for the advancement of the fields of optoelectronics and photonics. In this review, we summarise the ...
    • Anisotropic stimulated emission from aligned CdSe/CdS dot-in-rods 

      Gao, Y.; Ta, V. D.; Zhao, X.; Wang, Y.; Chen, R.; Zhao, Y.; Dang, C.; Sun, X.; Sun, H.; Demir, Hilmi Volkan (IEEE, 2014-10)
      Anisotropic optical properties of CdSe/CdS dot-in-rods loaded in a capillary tube are demonstrated, suggesting nanorods' alignment with a microfluidic approach. Polarized emissions from photoluminescence and whispering ...
    • Arrays of suspended plasmonic nanodiscs 

      Uran, Can; Demir, Hilmi Volkan (IEEE, 2013)
      We demonstrate lateral arrays of suspended metal nanodiscs, erected in parallel, partially encased in a dielectric-wrap using in-template synthesis with their polarization-dependent properties controlled as a function of ...
    • Asymmetric light propagation in chirped photonic crystal waveguides 

      Kurt H.; Yilmaz, D.; Akosman, A.E.; Özbay, Ekmel (Optical Society of American (OSA), 2012)
      We report numerical and experimental investigations of asymmetric light propagation in a newly designed photonic structure that is formed by creating a chirped photonic crystal (PC) waveguide. The use of a non-symmetric ...
    • Broadband one way propagation via dielectric waveguides with unequal effective index 

      Öner, B. B.; Üstün, K.; Kurt, H.; Okyay, Ali Kemal; Turhan-Sayan, G. (IEEE, 2014)
      We present an efficient approach for broad band one way propagation of light by parallel and unequal dielectric waveguides leading different effective phase shifts. Three dimensional numerical simulations show that 30% ...
    • Buried waveguides written deep inside silicon 

      Turnalı, Ahmet; Tokel, Onur; Kesim, Denizhan Koray; Makey, Ghaith; Elahi, Parviz; İlday, Fatih Ömer (OSA, 2017)
      Summary form only given. Silicon waveguides are widely used as optical interconnects and they are particularly important for Si-photonics. Si-based devices, along with other optical elements, are entirely fabricated on the ...
    • Compact left-handed metamaterial based on double-layer planar metal strip arrays 

      Guven, K.; Çalışkan, Deniz; Özbay, Ekmel (Optical Society of America, 2006)
      The existence of a left-handed transmission peak of a metamaterial consisting of double-layer planar metal strip arrays at 15 GHz is demonstrated. This design is very suitable to submicron scales required at communication ...
    • Design of all-silicon photonic and plasmonic perfect absorbers and their applications 

      Gök, Abdullah (Bilkent University, 2016-06)
      Majority of the optoelectronic devices works either in infrared regime or in visible spectrum. Among these, perfect absorbers attracted great attention due to their high applicability in solar cells and high performance ...
    • Electrically controlled resistive switching assisted active ultra-broadband optical tunability in the infrared 

      Battal, Enes; Özcan, Ayşe; Okyay, Ali Kemal (IEEE, 2013)
      We present an electrically tunable optical device with ultra-broadband tunability operating in 2-10 μm spectrum. We also, for the first time, optically observe resistive switching behavior in reflection measurements under ...
    • Electro-optic modulation of InAs quantum dot waveguides 

      Akça, İmran. B.; Dâna, Aykutlu; Aydınlı, Atilla; Rossetti, M.; Li, L.; Fiore, A.; Dağlı, N. (Technische Universiteit Eindhoven, 2008)
      The linear electro-optic properties in waveguides containing self-organized In As quantum dots were studied experimentally. Fabry-Perot measurements at 1515 nm on InAs/GaAs quantum dot structures yield a significantly ...
    • Enhancement and inhibition of photoluminescence in hydrogenated amorphous silicon nitride microcavities 

      Serpenguzel, A.; Aydinli, A.; Bek, A. (Optical Society of America, 1997-09-01)
      A Fabry-Perot microcavity is used for the enhancement and inhibition of photoluminescence in hydrogenated amorphous silicon nitride. The amplitude of the photoluminescence is enhanced 4 times, while its linewidth is reduced ...
    • Förster-type nonradiative energy transfer for assemblies of arrayed nanostructures: confinement dimension vs stacking dimension 

      Hernandez-Martinez, P. L.; Govorov, A. O.; Demir, Hilmi Volkan (American Chemical Society, 2014-02-11)
      Forster-type nonradiative energy transfer (NRET) provides us with the ability to transfer excitation energy between proximal nanostructures with high efficiency under certain conditions. Nevertheless, the well-known Forster ...
    • High-quality InP/ZnS nanocrystals with high photometric performance and their application to white quantum dot light-emitting diodes 

      Yang, X.; Tan, S. T.; Demir, Hilmi Volkan; Sun, X. W. (IEEE, 2012)
      Full visible range covering InP/ZnS core-shell nanocrystals with high photometric performance have been prepared. Making use of these nanocrystals, we demonstrate a white quantum dot LED with a high color rendering index ...
    • Highly flexible, full-color, top-emitting quantum dot light-emitting diode tapes 

      Yang X.; Mutlugün, Evren; Gao, Y.; Zhao, Y.; Tan, S.T.; Sun X.W.; Demir, Hilmi Volkan (IEEE, 2013)
      We report flexible tapes of high-performance, top-emitting, quantum dot based, light-emitting diodes (QLEDs) with multicolor emission, actively working even when flexed. The resulting QLED tapes reach a high peak luminance ...
    • In-chip microstructures and photonic devices fabricated by nonlinear laser lithography deep inside silicon 

      Tokel, O.; Turnalı, A.; Makey, G.; Elahi, P.; Çolakoǧlu, T.; Ergeçen E.; Yavuz, Ö.; Hübner R.; Borra, M. Z.; Pavlov, I.; Bek, A.; Turan, R.; Kesim, D. K.; Tozburun, S.; Ilday, S.; Ilday, F. Ö. (Nature Publishing Group, 2017)
      Silicon is an excellent material for microelectronics and integrated photonics 1-3, with untapped potential for mid-infrared optics 4 . Despite broad recognition of the importance of the third dimension 5,6, current ...
    • Large-area (> 50 cm × 50 cm), freestanding, flexible, optical membranes of Cd-free nanocrystal quantum dots 

      Mutlugün, Evren; Hernandez Martinez, Pedro L.; Eroğlu, Cüneyt; Coşkun, Yasemin; Erdem, Talha; Sharma, Vijay K.; Ünal, Emre; Panda, S. K.; Hickey, S. G.; Gaponik, N.; Eychmuller, A.; Demir, Hilmi Volkan (IEEE, 2012)
      Colloidal semiconductor quantum dots (QDs) have been extensively explored for numerous applications ranging from optoelectronics to biotechnology. This strong demand for the colloidal QDs arises because of their favorable ...
    • Large-area semi-transparent light-sensitive nanocrystal skins 

      Akhavan, Shahab; Güzeltürk, Burak; Sharma, Vijay Kumar; Demir, Hilmi Volkan (IEEE, 2012)
      Large area and semi-transparent highly light sensitive nanocrystal skin is demonstrated via spray-coating nanocrystals on top of polyelectrolyte-polymers based on photogenerated potential buildup where no external bias is ...
    • Low-cost, large-scale, ordered ZnO nanopillar arrays for light extraction efficiency enhancement in quantum dot light-emitting diodes 

      Yang, X.; Dev, K.; Wang, J.; Mutlugün, E.; Dang, C.; Zhao, Y.; Tan, S. T.; Sun, X. W.; Demir, Hilmi Volkan (IEEE, 2014)
      We report a QLED with enhanced light outcoupling efficiency by applying a layer of periodic ZnO nanopillar arrays. The resulting QLED reaches the record external quantum efficiency (EQE) of 9.34% in green-emitting QLEDs ...
    • Low-threshold optical gain and lasing of colloidal nanoplatelets 

      Keleştemur, Yusuf; Güzeltürk, Burak; Olutaş, Murat; Delikanlı, Savaş; Demir, Hilmi Volkan (IEEE, 2014-10)
      Semiconductor nanocrystals, which are also known as colloidal quantum dots (CQDs), are highly attractive materials for high performance optoelectronic device applications such as lasers. With their size, shape and composition ...
    • Modulation in InAs quantum dot waveguides 

      Akca, B. Imran; Dana, Aykutlu; Aydınlı, Atilla; Rossetti, M.; Li L.; Fiore, A.; Dagli, N. (Optical Society of America, 2007)
      Modulation in molecular beam epitaxy grown self-assembled InAs quantum dot waveguides have been studied at 1500 nm as a function of wavelength and voltage. Enhanced electro-optic coefficients compared to bulk GaAs were ...