Researcher:
Ataman, Çağlar

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PhD Student

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Çağlar

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Ataman

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Ataman, Çağlar

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2004 - 200916

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Researcher Of Publications: search.filters.isAuthorOfPublication.f7ba102a-19d9-4700-83b2-0996262a1329

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Now showing 1 - 10 of 16
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    High-resolution beam steering using microlens arrays
    (Optical Soc Amer, 2006) N/A; N/A; Department of Electrical and Electronics Engineering; Akatay, Ata; Ataman, Çağlar; Ürey, Hakan; Master Student; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 8579
    Imaging or beam-steering systems employing a periodic array of microlenses or micromirrors suffer from diffraction problems resulting from the destructive interference of the beam segments produced by the array. Simple formulas are derived for beam steering with segmented apertures that do not suffer from diffraction problems because of the introduction of a moving linear phase shifter such as a prescan lens before the periodic structure. The technique substantially increases the resolution of imaging systems that employ microlens arrays or micromirror arrays. Theoretical, numerical, and experimental results demonstrating the high-resolution imaging concept using microlens arrays are presented.
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    Modeling and characterization of comb-actuated resonant microscanners
    (Iop Publishing Ltd, 2006) N/A; Department of Electrical and Electronics Engineering; Ataman, Çağlar; Ürey, Hakan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579
    The dynamics of the out-of-plane comb-drive actuator used in a torsional resonant mode microscanner is discussed. The microscanner is fabricated using the standard SOI technology by Fraunhofer, IPMS and utilized in various display, barcode scanning, spectroscopy and other imaging applications. The device is a parametrically excited system and exhibits hysteretic frequency response, nonlinear transient response, subharmonic oscillations, multiple parametric resonances, and alternating-oscillation-frequency behavior. Analytical and numerical models are developed to predict the parametric system dynamics. The analytical model is based on the solution of the linear Mathieu equation and valid for small angular displacements. The numerical model is valid for both small and large deflection angles. The analytical and numerical models are validated with the experimental results under various ambient pressures and excitation schemes and successfully predict the dynamics of the parametric nature of the microscanner. As many as four parametric resonances are observed at 30 mTorr. The models developed in this paper can be used to optimize the structure and the actuator.
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    Mechanically coupled comb drive MEMS stages
    (IEEE, 2008) Hedsten, Karin; Enoksson, Peter; Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; Arslan, Aslıhan; Ataman, Çağlar; Holmstrom, Sven; Seren, Hüseyin Rahmi; Ürey, Hakan; Researcher; PhD Student; Researcher; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; N/A; 8579
    An electrostatic large clear-aperture in-plane scanner with a novel actuation principle is presented for fast and large stroke scanning applications. 9 pm resonant deflection at 11.51 KHz with 100 Vpp excitation is observed.
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    Nonlinear frequency response of comb-driven microscanners
    (SPIE-Soc Photoptical Instrumentation Engineers, 2004) N/A; Department of Electrical and Electronics Engineering; Ataman, Çağlar; Ürey, Hakan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579
    Accurate prediction of the dynamic behavior of comb-driven MEMS microscanners is important to optimize the actuator and structure design. In this paper, a numerical and an analytical model for the dynamic analysis of comb-driven microscanners under different excitation schemes are presented. The numerical model is based on a second order nonlinear differential equation. Due to the nature of the torque function, this governing equation of motion is a parametric nonlinear ODE, which exhibits hysteretic frequency domain behavior and subharmonic oscillations. Experimental results and approximate analytical expressions for this nonlinear torque function of the comb-drive are presented. Amplitude and phase relationship between the excitation signal and the resultant oscillations at different excitation frequencies are measured and we show that they are in close agreement with the numerical simulations. Analytical model uses perturbation methods to reach approximate close-form expressions for the dynamic behavior of the device in the first parametric resonance region. It is also utilized to predict the stability regions on the frequency-excitation voltage plane, where the device exhibit hysterical characteristics. Analytical and numerical modeling approaches proposed in this paper provides a simple yet powerful way to analyze the nonlinear frequency response of comb-driven actuators and simplify the design process for a microscanner based system.
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    Miniaturized FR4 spectrometers
    (Ieee, 2009) N/A; N/A; N/A; N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; N/A; Department of Electrical and Electronics Engineering; Seren, Hüseyin Rahmi; Ferhanoğlu, Onur; Hatipoğlu, Gökhan; Boyman, Mişel; Ölçer, Selim; Ataman, Çağlar; Ürey, Hakan; Master Student; PhD Student; Master Student; Undergraduate Student; Other; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 205198; N/A; N/A; N/A; N/A; 8579
    A miniaturized and electromagnetically driven FR4 based moving platform is developed for Fourier Transform spectrometer applications. Both Michelson interferometer and Lamellar Grating interferometer configurations are demonstrated. +/- 500 mu m translational motion (corresponding to 5 cm(-1) spectral resolution) is demonstrated with the moving platform. Two methods are proposed and partially demonstrated for pure translational motion: (I) integrated control system using a quad photo detector feedback and (2) corner cube retroreflector. The fundamental advantages and the limits of the lamellar grating interferometers are also discussed.
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    A Fourier transform spectrometer using resonant vertical comb actuators
    (Institute of Physics (IOP) Publishing, 2006) Wolter, Alexander; N/A; Department of Electrical and Electronics Engineering; Ataman, Çağlar; Ürey, Hakan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579
    The design, fabrication and characterization of a novel out-of-plane vertical comb-drive actuator based lamellar grating interferometer (LGI) is reported. The interferometer utilizes resonant mode vertical comb actuators, where comb fingers are simultaneously used for actuation and as a movable diffraction grating, making the device very compact. The Fourier transform of the zeroth order intensity pattern as a function of the optical path difference gives the spectrum of light. The main advantages offered by the proposed device are a long travel range (i.e. good spectral resolution), a large clear aperture (i.e. high light efficiency), and a very simple, robust and compact spectrometer structure. Peak-to-peak 106 mu m out-of-plane deflection is observed in ambient pressure and at 28 V, corresponding to a theoretical spectral resolution of about 0.4 nm in the visible band and 3.6 nm at 1.5 mu m. A simple CMOS compatible process based on bulk micromachining of a silicon-on-insulator wafer is used for the device fabrication.
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    Compact fourier transform spectrometers using FR4 platform
    (Elsevier Science Sa, 2009) N/A; Department of Electrical and Electronics Engineering; Ataman, Çağlar; Ürey, Hakan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579
    A novel magnetic actuated polymer optical platform is integrated into lamellar grating and Michelson type Fourier transform spectrometers. The proposed advantages of the novel platform over existing approaches, such as MEMS spectrometers, or bulky FTIR systems, include millimeter range dimensions providing a large clear aperture and enabling conventional machining for device fabrication, a controllable AC and/or DC motion both in rotational and translational modes, and real-time measurement. The platform is capable of achieving +/- 250 mu m DC deflection (i.e., 20cm(-1) frequency resolution) in ambient pressure in the translational mode. A spectral resolution of 0.89 nm at 638 nm is demonstrated using this platform in a Michelson interferometer configuration. In addition, an overview of system integration methods including an optical position feedback mechanism is also discussed. (C) 2009 Published by Elsevier B.V.
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    Vertical resonant comb actuators for fourier transform spectroscopy
    (IEEE-Inst Electrical Electronics Engineers Inc, 2006) N/A; Department of Electrical and Electronics Engineering; Ataman, Çağlar; Ürey, Hakan; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 8579
    A Fourier Transform Spectrometer is implemented with resonant mode out-of-plane comb actuators which are used as movable diffraction gratings. 106μm deflection is obtained at 28V in ambient pressure at 1.2 KHz for a 3mm clear aperture device.
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    FR-4 as a new MOEMS platform
    (Ieee, 2007) N/A; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; N/A; N/A; Department of Electrical and Electronics Engineering; Holmstrom, Sven; Yalçınkaya, Arda Deniz; Işıkman, Serhan Ömer; Ataman, Çağlar; Ürey, Hakan; Researcher; Researcher; Master Student; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; College of Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 144523; N/A; N/A; 8579
    FR4 is a well-engineered material and widely used in the PCB industry and lend itself to high degree of integration of optoelectronic, micro-optic, and electronic devices. FR4 is used for the first time as an actuated mechanical device that integrates several functions on the same device. Two different approaches to 2D laser scanning using a single electromagnetic actuation coil and application to Fourier Transform spectroscopy are presented; many other applications can be envisioned.
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    Two-axis MENIS scanner for display and imaging applications
    (IEEE-Inst Electrical Electronics Engineers Inc, 2005) Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; Department of Electrical and Electronics Engineering; N/A; N/A; N/A; Department of Mechanical Engineering; Ürey, Hakan; Yalçınkaya, Arda Deniz; Brown, Dean; Anaç, Ozan; Ataman, Çağlar; Başdoğan, İpek; Faculty Member; Researcher; Researcher; N/A; N/A; Master Student; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Department of Mechanical Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; 8579; 144523; N/A; N/A; N/A; N/A; N/A; 179940
    Two-axis gimbaled scanner used in an SVGa display product with 58deg optical scan angle, 1.5mm mirror size, and 21.KHz resonant frequency is reported Scanner is actuated electromagnetically using a single coil on the outer frame and by mechanical coupling of outer frame motion into the inner mirrorframe.