Browsing by Keywords "Wave propagation"
Now showing items 117 of 17

Condition number in recovery of signals from partial fractional fourier domain information
(2013)The problem of estimating unknown signal samples from partial measurements in fractional Fourier domains arises in wave propagation. By using the condition number of the inverse problem as a measure of redundant information, ... 
The effect of distribution of information on recovery of propagating signals
(Bilkent University, 201509)Interpolation is one of the fundamental concepts in signal processing. The analysis of the di fficulty of interpolation of propagating waves is the subject of this thesis. It is known that the information contained in a ... 
Electricallyreconfigurable integrated photonic switches
(2004)We report remotely electrically reconfigurable photonic switches that intimately integrate waveguide electroabsorption modulators with surfacenormal photodiodes, avoiding conventional electronics. These switches exhibit ... 
Enhanced transmission of electromagnetic waves through splitring resonatorshaped apertures
(Society of PhotoOptical Instrumentation Engineers (SPIE), 20110621)The design of aperture shape is a promising approach for enhanced transmission through a subwavelength aperture. We designed splitringresonator (SRR)shaped apertures in order to increase the transmission through ... 
Experimental observation of lefthanded transmission in a bilayer metamaterial under normaltoplane propagation
(Optical Society of American (OSA), 2006)We demonstrate experimentally the doublenegative (ε < 0, μ < 0) transmission band of a onedimensional metamaterial structure under normaltoplane propagation in the microwave regime. The structure consists of stacked ... 
Fast and accurate linear canonical transform algorithms
(Institute of Electrical and Electronics Engineers Inc., 2015)Linear canonical transforms are encountered in many areas of science and engineering. Important transformations such as the fractional Fourier transform and the ordinary Fourier transform are special cases of this transform ... 
Highly directive radiation and negative refraction using photonic crystals
(Institute of Physics Publishing, 2005)In this article, we present an experimental and numerical study of certain optical properties of twodimensional dielectric photonic crystals (PCs). By modifying the band structure of a twodimensional photonic crystal ... 
Integral imaging using phaseonly LCoS spatial light modulators as Fresnel lenslet arrays
(Optical Society of Amercia, 20111027)We present a digital integral imaging system. A Fresnel lenslet array pattern is written on a phaseonly LCoS spatial light modulator device (SLM) to replace the regular analog lenslet array in a conventional integral ... 
Local error analysis arising from the conventional scalar approximation in wide optical fields
(Institute of Electrical and Electronics Engineers Inc., 2017)The scalar approximation which is used to represent the optical fields in free space causes large error in large angles due to the neglected longitudinal component of the vector electric field. A short space Fourier transform ... 
On the elemination of infinities in the PO component of equivalent edge currents
(Elsevier, 1993)Equivalent edge currents for the Physical Optics (PO) contribution to the edge diffraction are derived by choosing a proper coordinate system for a half plane. It is seen that these expressions for the PO component are ... 
Phase retrieval from electric field intensity for wide angle optical fields
(OSA  The Optical Society, 2017)An intensity preserving scalar to vector electric field mapping, in a wave propagation environment, based on a filtering procedure is proposed. In a phase retrieval problem, the proposed mapping outperforms the conventional ... 
Power spectrum equalized scalar representation of wideangle optical field propagation
(Springer New York LLC, 2018)It may be desirable to represent optical fields using scalar approximations, due to its simplicity. Since the optical field is an electromagnetic wave, in order to implement an optical setup, a mapping from such a scalar ... 
Signal recovery with costconstrained measurements
(IEE, 20100322)We are concerned with the problem of optimally measuring an accessible signal under a total cost constraint, in order to estimate a signal which is not directly accessible. An important aspect of our formulation is the ... 
Topological insulator based locally resonant phononic crystals: wave propagation and acoustic band gaps
(Taylor and Francis Inc., 2016)ABSTRACT: In the present work the acoustic band structure of a twodimensional phononic crystal (PC) containing an organic ferroelectric (PVDF polyvinylidene fluoride) and topological insulator (Bi2Te3) were investigated ... 
Verification of impedance matching at the surface of lefthanded materials
(Wiley, 2006)Impedance matching at the surface of lefthanded materials (LHM) is required for certain applications including a perfect lens. In this study, we present the experimental and theoretical verification of an impedancematched ... 
Wave propagation in metamaterial structures and retrieval of homogenization parameters
(Bilkent University, 2007)Electromagnetic wave propagation in metamaterial structures (metamaterial slabs, metamaterial cylinders, metamaterial coated conducting cylinders etc.) are investigated. Scattered and transmitted electromagnetic fields ... 
Wideband 'black silicon' for midinfrared applications
(Institute of Physics Publishing, 2017)In this paper, we investigate the absorption of midinfrared light by low resistivity silicon textured via deep reactive ion etching. An analytical description of the wave propagation in black silicon texture is presented, ...