Koç University is a non-profit private university in Istanbul, Turkey. It started education in temporary buildings in İstinye in 1993, and moved to its current Rumeli Feneri campus near Sarıyer in 2000. University currently consists of Colleges of Social science and Humanities, Administrative science and Economics, Science, Engineering, Law, Nursing and Medicine. Koç University offers 22 undergraduate, 31 graduate and 16 PhD programs. Wikipedia.
Mostafazadeh A.,Koc University
Physical Review Letters
We introduce a notion of spectral singularity that applies for a general class of nonlinear Schrödinger operators involving a confined nonlinearity. The presence of the nonlinearity does not break the parity-reflection symmetry of spectral singularities but makes them amplitude dependent. Nonlinear spectral singularities are, therefore, associated with a resonance effect that produces amplified waves with a specific amplitude-wavelength profile. We explore the consequences of this phenomenon for a complex δ-function potential that is subject to a general confined nonlinearity. © 2013 American Physical Society. Source
Mostafazadeh A.,Koc University
Physical Review A - Atomic, Molecular, and Optical Physics
For a general complex scattering potential defined on a real line, we show that the equations governing invisibility of the potential are invariant under the combined action of parity and time-reversal (PT) transformation. We determine the PT-symmetric as well as non-PT-symmetric invisible configurations of an easily realizable exactly solvable model that consists of a two-layer planar slab consisting of optically active material. Our analysis shows that although PT symmetry is neither necessary nor sufficient for the invisibility of a scattering potential, it plays an important role in the characterization of the invisible configurations. A byproduct of our investigation is the discovery of certain configurations of our model that are effectively reflectionless in a spectral range as wide as several hundred nanometers. © 2013 American Physical Society. Source
Koç University and Turk Telekomunikasyon A.S. | Date: 2013-05-24
A haptic display with a touch screen surface enabled to be tactically detectable by the addition of a thin-film piezo stimulator thereto is disclosed. A modeling for minimized power consumption and a maximized tactile detection on the display is also disclosed. The haptic screen, during operation of a touch screen, enables a user to have a haptic interaction with the screen through vibrations generated on the touch surface. A piezo placement model enables to achieve vibrations of specific values at each spot on the screen where the user touches, through the use of a minimum number of piezo components of the screen so as to provide an optimum tactile detection and minimum power consumption. Pre-defined values of amplitude and frequency are applied to ensure that the vibration is detected in accordance with the placement model and pre-defined values of the placement model are used depending on the position of touch.
Koç University | Date: 2013-04-19
Koç University and MicroVision | Date: 2013-01-17
A transparent screen includes a microlens array. The microlens array includes microlenses that are individually rotated to reflect a projected image to a common eyebox. The microlenses may have a dichroic coating to reflect narrowband light. An automotive windshield may include an embedded microlens array as part of a head up display. Eyewear includes an eyepiece with a rotated microlens array and a projector to project content on the microlens array.