Browsing by Author "Umul, Yusuf Z."

Now showing 1 - 20 of 27

Citation - WoS: 22
Citation - Scopus: 23
Alternative Interpretation of the Edge-Diffraction Phenomenon
(Optical Soc Amer, 2008) Umul, Yusuf Z.
An alternative interpretation of the phenomenon of edge diffraction is proposed according to a new separation of the Fresnel function. The subfields are investigated in the problem of diffraction of a plane wave by a perfectly conducting half-plane, and the results are compared numerically with other interpretations. (c) 2008 Optical Society of America.
Citation - WoS: 14
Citation - Scopus: 15
Closed Form Series Solution of the Diffraction Problem of Plane Waves by an Impedance Half-Plane
(Iop Publishing Ltd, 2009) Umul, Yusuf Z.
The scattering problem of plane waves by an impedance half-plane is solved by using the method of separation of variables, and a closed form series expression, which separately reduces to the cases of soft and hard half-planes, is obtained. The results are investigated numerically and compared with the solutions in the literature.
Comment on "a Survey of the New Proposal About the Photon Momentum" (Vol 148, Pg 342, 2017)
(Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf Z.
Citation - WoS: 34
Citation - Scopus: 37
Diffraction of Evanescent Plane Waves by a Resistive Half-Plane
(Optical Soc Amer, 2007) Umul, Yusuf Z.
Diffraction of evanescent plane waves by a resistive half-plane is examined. The scattering integrals are constructed with the modified theory of physical optics. These integrals are evaluated uniformly by using an unusual method. The scattered fields of evanescent waves are obtained by giving the angle of incidence a complex value. The diffracted waves are plotted numerically for different parameters of the incident field. (c) 2007 Optical Society of America.
Citation - WoS: 8
Citation - Scopus: 8
Diffraction of Homogeneous and Inhomogeneous Plane Waves by a Planar Junction Between Perfectly Conducting and Impedance Half-Planes
(Optical Soc Amer, 2007) Umul, Yusuf Z.
The problem of diffraction of homogeneous and inhomogeneous plane waves at the discontinuity formed by perfectly conducting and impedance half-planes is examined by the method of modified theory of physical optics (MTPO). The MTPO integral of the reflected scattered waves by the perfectly conducting half-plane is reconstructed in order to include the effect of the diffracted wave coming from the edge of the impedance halfplane. The integrals are evaluated by a uniform asymptotic method. The results are plotted numerically and compared with the literature. (C) 2007 Optical Society of America
Citation - WoS: 3
Citation - Scopus: 4
Diffraction of Plane Waves by a Black Wedge
(Elsevier Sci Ltd, 2010) Umul, Yusuf Z.
The scattering of plane waves by a black wedge is examined. Two methods are considered for the solution of the problem. A closed-form series solution is derived by performing the technique of the separation of variables using boundary conditions of Macdonald. The second approach is the method of the modified theory of physical optics. The results are compared numerically. (C) 2009 Elsevier Ltd. All rights reserved.
Citation - WoS: 15
Citation - Scopus: 15
Diffraction of Waves by a Resistive Half-Plane
(Elsevier Science Bv, 2014) Umul, Yusuf Z.
The scattered waves by a resistive half-plane are investigated with defining reflection and transmission coefficients for the diffracted waves. The coefficients are determined according to suitable conditions that are derived from the boundary conditions and the limiting cases of the reflection and transmission coefficients of the geometrical optics fields. The resultant field expressions are examined and compared with the literature numerically. (C) 2014 Elsevier By All rights reserved.
Citation - WoS: 23
Citation - Scopus: 24
Edge-Dislocation Waves in the Diffraction Process by an Impedance Half-Plane
(Optical Soc Amer, 2007) Umul, Yusuf Z.
Edge-dislocation waves, created in the diffraction of plane waves by an impedance half-plane, are examined by the method of modified theory of physical optics. The integrals, obtained by a related technique, are decomposed according to their boundaries and evaluated by using uniform asymptotic methods. The results are plotted and are investigated numerically. (c) 2007 Optical Society of America
Citation - WoS: 15
Citation - Scopus: 15
Effect of the Shadow Geometry on Diffraction
(Optical Soc Amer, 2008) Umul, Yusuf Z.
The effect of the scatterer surface on the shadow region is examined by using the surface integrals of the modified theory of physical optics. It is shown that the shadow geometry has a considerable effect on the structure of the edge diffracted waves. The diffracted fields for the illuminated and shadowed surface of a half-plane are evaluated in terms of Fresnel integrals and plotted numerically. (C) 2008 Optical Society of America
Citation - WoS: 5
Citation - Scopus: 5
Fringe Waves in Wedge Diffraction
(Elsevier Gmbh, Urban & Fischer verlag, 2012) Umul, Yusuf Z.
Explicit expressions for the non-uniform currents of the physical theory of diffraction are derived in terms of Fresnel functions for wedge diffraction by taking into account the surface integrals of the modified theory of physical optics. The obtained fringe waves are compared numerically by the asymptotic representations, found in the literature. (C) 2011 Elsevier GmbH. All rights reserved.
Citation - WoS: 6
Citation - Scopus: 8
General Formulation of the Scattered Matter Waves by a Quantum Shutter
(2009) Umul, Z. Yusuf; Umul, Yusuf Z.
The scattering process of matter waves by a quantum shutter is investigated by using the spectrum integral representation. The scattered fields are expressed in terms of the Fresnel function. It is shown that the obtained equation gives the Moshinsky function for a one dimensional problem of the plane wave. Also a general integral representation is derived for two dimensional problems. The scattering of matter waves for some special wave-packets are examined analytically and numerically.
Citation - WoS: 1
Citation - Scopus: 1
Interaction of Electromagnetic Waves With a Resistive Half-Plane
(Springer France, 2016) Umul, Yusuf Z.
The interaction process of electromagnetic waves by a resistive half-plane is investigated. The scattered geometrical optics fields are obtained by subtracting the incident field from the total geometrical optics waves. The physical optics integral of the scattered waves is derived with the aid of the scattered geometrical optics fields. The edge diffracted waves are derived from the physical optics integral by the edge point technique. A correction field is added to the diffracted fields in order to obtain a solution that satisfies the resistive boundary conditions on the surface of the half-screen. The uniform diffracted fields are expressed in terms of the Fresnel function and the resultant field representations are compared with the literature numerically.
Citation - WoS: 39
Citation - Scopus: 43
Modified Diffraction Theory of Kirchhoff
(Optical Soc Amer, 2008) Umul, Yusuf Z.
The diffraction theory of Kirchhoff is reinterpreted and a new form of a surface diffraction integral is developed by using the axioms of the modified theory of physical optics, which leads to the exact scattered fields by conducting bodies. The new integral is arranged according to the interpretation of Young, and the diffracted waves are expressed in terms of a line integral. The method is applied to the diffraction problem by a semi-infinite edge contour. (c) 2008 Optical Society of America.
Citation - WoS: 1
Citation - Scopus: 2
Modified Theory of Physical Optics Approach To Diffraction by an Interface Between Pemc and Absorbing Half-Planes
(Lgep-supelec, 2021) Umul, Yusuf Z.
The scattering of electromagnetic plane waves by an interface, located between perfect electromagnetic conductor and absorbing half-planes, is investigated. The perfect electromagnetic conductor half-plane is divided into perfect electric conductor and perfect magnetic conductor half-screens. The same decomposition is done for the absorbing surface. Then four different geometries are defined according to this approach. The scattered fields by the four sub-problems are obtained with the aid of the modified theory of physical optics. The resultant scattering integrals are combined in a single expression by using key formulas, defined for the perfect electromagnetic conductor and absorbing surfaces. The diffracted and geometric optics fields are obtained by the asymptotic evaluation of the scattering integral for large values of the wave-number. The behaviors of the derived field expressions are analyzed numerically.
Citation - WoS: 52
Citation - Scopus: 55
Modified Theory of Physical Optics Solution of Impedance Half Plane Problem
(Ieee-inst Electrical Electronics Engineers inc, 2006) Umul, Yusuf Z.
The scattering of electric polarized plane waves from an impedance half plane problem is examined by the method of modified theory of physical optics (MTPO). Two integrals, consisting of incident and reflected scattered fields, are obtained. These integrals are evaluated asymptotically by the methods of stationary phase and edge point. The obtained scattered fields are compared with the exact solution numerically.
Citation - WoS: 33
Citation - Scopus: 36
Mtpo Based Potential Function of the Boundary Diffraction Wave Theory
(Elsevier Sci Ltd, 2008) Umul, Yusuf Z.
A novel potential function is introduced by using the modified theory of physical optics integrals for a perfectly conducting half-plane. The function is valid for arbitrary aspects of observation. The line integration of these functions gives the total scattered fields. The method is applied to the problem of diffraction of plane waves by an opaque half-plane for oblique incidence. (c) 2008 Elsevier Ltd. All rights reserved.
Citation - WoS: 3
Citation - Scopus: 4
The Physical Optics Integral on the Scatterer's Unlit Surface
(Elsevier Gmbh, 2014) Umul, Yusuf Z.
The scattering integrals of the modified theory of physical optics are redefined according to the illuminated and unlit surfaces of the scattering object. With this aim the canonical problem of wedge diffraction is taken into account. It is shown that the new scattering integral contain two geometrical optics and diffracted fields. One of the geometrical optics waves is the reflected field component that propagates in the real space. The other one transmits to an imaginary space through the scattering surface and does not have any influence in the real space. The diffracted waves exist in the real space and satisfy the related boundary condition on the scattering surfaces. The resultant field expressions are compared with the exact series solution of the problem numerically. (C) 2014 Elsevier GmbH. All rights reserved.
Citation - WoS: 1
Citation - Scopus: 1
The Relation Between Wave Vector and Momentum in Quantum Mechanics
(Elsevier Gmbh, 2016) Umul, Yusuf Z.
The fundamental relation of quantum mechanics, which correlates the momentum of a quantum particle to the wave vector of the matter wave, is re-interpreted. The wave vector, in the relation, is formulized as the integration of it along the angular coordinates for two and three dimensional cases. Various evaluations of the wave vector are performed for different types of waves and the results are discussed. Also the edge diffracted fields are considered according to the new interpretation. (C) 2016 Elsevier GmbH. All rights reserved.
Citation - WoS: 7
Citation - Scopus: 9
Rubinowicz Transform of the Mtpo Surface Integrals
(Elsevier Science Bv, 2008) Umul, Yusuf Z.
The surface integral of the modified theory of physical optics is reduced to a line integral by using the Rubinowicz transform for the incident scattered fields by an arbitrary aperture in a black surface. The integral theorem of Kirchhoff is applied to the scattering geometry and the diffracted fields are expressed in terms of a line integral along the contour of the diffracting edge. (C) 2008 Elsevier B.V. All rights reserved.
Citation - WoS: 11
Citation - Scopus: 11
Scattered Fields of Conducting Half-Plane Between Two Dielectric Media
(Optical Soc Amer, 2010) Yalcin, Ugur; Umul, Yusuf Z.
We investigate the scattering process of plane waves by a conducting half-plane between two dielectric media by introducing novel boundary conditions, in terms of soft and hard surfaces. The cases of soft and hard half-planes are studied independently. The scattered waves are examined numerically. The numerical results show that the behavior of the fields is in harmony with the theory. The transition between the two dielectric media is continuous, and the structure of the method enables one also to examine more complex geometries, such as wedges having soft and hard boundary conditions. (C) 2010 Optical Society of America