Now showing items 1-20 of 22

    • 45-GHz bandwidth-efficiency resonant-cavity-enhanced ITO-Schottky photodiodes 

      Bıyıklı, Necmi; Kimukin, I.; Aytür, O.; Gökkavas, M.; Ünlü, M. S.; Özbay, Ekmel (IEEE, 2001)
      High-speed Schottky photodiodes suffer from low efficiency mainly due to the thin absorption layers and the semitransparent Schottky-contact metals. We have designed, fabricated and characterized high-speed and high-efficiency ...
    • Analysis of Gaussian-beam degenerate optical parametric amplifiers for the generation of quadrature-squeezed states 

      Köprülü, K. G.; Aytür, O. (American Physical Society, 1999-11)
      This paper investigates the generation of quadrature-squeezed states of light using a degenerate optical parametric amplifier (DOPA) that is pumped by a focused Gaussian beam. The formulation that is presented facilitates ...
    • Analysis of the generation of amplitude-squeezed light with Gaussian-beam degenerate optical parametric amplifiers 

      Köprülü, K. G.; Aytür, O. (OSA Publishing, 2001-06)
      We investigate the generation of amplitude-squeezed states with degenerate optical parametric amplifiers that are pumped by focused Gaussian beams. We present a model that facilitates the calculation of the squeezing level ...
    • Fabrication of high-speed resonant cavity enhanced schottky photodiodes 

      Özbay, Ekmel; Islam, M. S.; Onat, B.; Gökkavas, M.; Aytür, O.; Tuttle, G.; Towe, E.; Henderson, R. H.; Ünlü, M. S. (Institute of Electrical and Electronics Engineers, 1997-05)
      We report the fabrication and testing of a GaAs-based high-speed resonant cavity enhanced (RCE) Schottky photodiode. The top-illuminated RCE detector is constructed by integrating a Schottky contact, a thin absorption ...
    • Femtosecond optical parametric oscillator based on periodically poled KTiOPO4 

      Kartaloğlu, T.; Köprülü, K. G.; Aytür, O.; Sundheimer, M.; Risk, W. P. (1998-01-01)
      We report a femtosecond optical parametric oscillator based on a periodically poled KTiOPO4 crystal for which quasi-phase matching is achieved with a 24-μm poling period. The singly resonant parametric oscillator, synchronously ...
    • Femtosecond self-doubling optical parametric oscillator based on KTiOAsO4 

      Kartaloğlu, T.; Aytür, O. (IEEE, 2003)
      We report a femtosecond intracavity-frequency-doubled optical parametric oscillator that employs a single KTiOAsO4 crystal for both parametric generation and frequency doubling. This device generates a yellow output beam ...
    • Fractional Fourier domains 

      Özaktaş, Haldun M.; Aytür, O. (Elsevier BV, 1995-09)
      It is customary to define the time-frequency plane such that time and frequency are mutually orthogonal coordinates. Representations of a signal in these domains are related by the Fourier transform. We consider a continuum ...
    • High-performance solar-blind photodetectors based on AlxGa 1_xN heterostructures 

      Özbay, Ekmel; Bıyıklı, Necmi; Kimukin, I.; Kartaloglu, T.; Tut, T.; Aytür, O. (IEEE, 2004)
      Design, fabrication, and characterization of high-performance AI xGa1-xN-based photodetectors for solar-blind applications are reported. AlxGa1-xN heterostructures were designed for Schottky. p-i-n, and metal-semicondnctor-metal ...
    • High-speed >90% quantum-efficiency p-i-n photodiodes with a resonance wavelength adjustable in the 795-835 nm range 

      Özbay, Ekmel; Kimukin, İ.; Bıyıklı, Necmi; Aytür, O.; Gökkavas, M.; Ulu, G.; Ünlü, M. S.; Mirin, R. P.; Bertness, K. A.; Christensen, D. H. (A I P Publishing LLC, 1999-02-22)
      We report GaAs/AlGaAs-based high-speed, high-efficiency, resonant cavity enhanced p-i-n photodiodes. The devices were fabricated by using a microwave-compatible fabrication process. By using a postprocess recess etch, we ...
    • High-speed GaAs-based resonant-cavity-enhanced 1.3 μm photodetector 

      Kimukin, I.; Özbay, Ekmel; Bıyıklı, Necmi; Kartaloğlu, T.; Aytür, O.; Unlu, S.; Tuttle, G. (American Institute of Physics., 2000)
      We report GaAs-based high-speed, resonant-cavity-enhanced, Schottky barrier internal photoemission photodiodes operating at 1.3 μm. The devices were fabricated by using a microwave-compatible fabrication process. Resonance ...
    • High-speed high-efficiency resonant cavity enhanced photodiodes 

      Özbay, Ekmel; Kimukin, I.; Bıyıklı, N.; Aytür, O.; Gökkavas, M.; Ulu, G.; Ünlü, M. S.; Mirin, R. P.; Bertness, K. A.; Christensen, D. H.; Towe, E.; Tuttle, G. (Society of Photo-Optical Instrumentation Engineers, Bellingham, WA, United States, 1999)
      In this paper, we review our research efforts on RCE high-speed high-efficiency p-i-n and Schottky photodiodes. Using a microwave compatible planar fabrication process, we have designed and fabricated GaAs based RCE ...
    • High-Speed InSb photodetectors on GaAs for mid-IR applications 

      Kimukin, I.; Bıyıklı, Necmi; Kartaloǧlu, T.; Aytür, O.; Özbay, Ekmel (IEEE, 2004)
      We report p-i-n type InSb-based high-speed photodetectors grown on GaAs substrate. Electrical and optical properties of photodetectors with active areas ranging from 7.06 × 10 -6 cm 2 to 2.25 × 10 -4 cm 2 measured at 77 K ...
    • Highly efficient wavelength conversion of Q-switched Nd: YAG lasers into a red wavelength 

      Figen, Z. G.; Yalabik, A.; Aytür, O. (Institute of Electrical and Electronics Engineers, 2006)
      We report a nanosecond upconversion optical parametric oscillator which can convert the output of a Nd:YAG laser at 1064-nm wavelength into 627 nm with high efficiency. This device is based on a single KTiOAsO4 crystal ...
    • Idler-efficiency-enhanced long-wave infrared beam generation using aperiodic orientation-patterned GaAs gratings 

      Figen, Z. G.; Aytür, O.; Arıkan, Orhan (Optical Society of America, 2016)
      In this paper, we design aperiodic gratings based on orientation-patterned gallium arsenide (OP-GaAs) for converting 2.1 μm pump laser radiation into long-wave infrared (8-12 μm) in an idler-efficiency-enhanced scheme. ...
    • ITO-schottky photodiodes for high-performance detection in the UV-IR spectrum 

      Bıyıklı, Necmi; Kimukin, I.; Butun, B.; Aytür, O.; Özbay, Ekmel (IEEE, 2004)
      High-performance vertically illuminated Schottky photodiodes with indium-tin-oxide (ITO) Schottky layers were designed, fabricated, and tested. Ternary and quarternary III-V material systems (AlGaN-GaN, AlGaAs-GaAs, ...
    • Non-orthogonal domains in phase space of quantum optics and their relation to fractional Fourier transforms 

      Aytür, O.; Özaktaş, Haldun M. (Elsevier BV * North-Holland, 1995-10-15)
      It is customary to define a phase space such that position and momentum are mutually orthogonal coordinates. Associated with these coordinates, or domains, are the position and momentum operators. Representations of the ...
    • Operational approach to quantum limits on polarization measurement 

      Hakioğlu, T.; Shumovsky, A. S.; Aytür, O. (Elsevier, 1994)
      We discuss the polarization measurement of a fully polarized coherent field in the weak intensity quantum limit within the framework of operational approach which was recently discussed by Noh, Fougéres and Mandel. We ...
    • Phase-matched self-doubling optical parametric oscillator 

      Kartaloğlu, T.; Köprülü, K. G.; Aytür, O. (Optical Society of America, 1997-03-01)
      We report a synchronously pumped intracavity frequency-doubled optical parametric oscillator that employs a single KTiOPO4 crystal for both parametric generation and frequency doubling. Both nonlinear processes are phase ...
    • Plane-wave dynamics of optical parametric oscillation with simultaneous sum-frequency generation 

      Dikmelik, Y.; Akgün, G.; Aytür, O. (Institute of Electrical and Electronics Engineers, 1999-06)
      This paper presents a theoretical analysis of sum-frequency generating optical parametric oscillators where a single nonlinear crystal is used for both parametric generation and sum-frequency generation. In these devices, ...
    • Plane-wave theory of self-doubling optical parametric oscillators 

      Aytür, O.; Dikmelik, Y. (Institute of Electrical and Electronics Engineers, 1998-03)
      This paper presents a theoretical analysis of self-doubling optical parametric oscillators (OPO's) where a single nonlinear crystal is used for both parametric generation and frequency doubling. In these devices, the ...