Browsing by Author "Benson, T. M."
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Item Open Access Characteristic equations for the lasing Modes of infinite periodic chain of quantum wires(IEEE, 2008-06) Byelobrov, V. O.; Benson, T. M.; Altıntaş, Ayhan; Nosich, A.I.In this paper, we study the lasing modes of a periodic open optical resonator. The resonator is an infinite chain of active circular cylindrical quantum wires standing in tree space. Characteristic equations for the frequencies and associated linear thresholds of lasing are derived. These quantities are considered as eigenvalues of specific electromagnetic-field problem with "active" imaginary part of the cylinder material's refractive index - Lasing Eigenvalue Problem (LEP). ©2008 IEEE.Item Open Access Enhancement of plasmon resonances in the wave scattering by finite grids of circular silver wires(IEEE, 2010-09) Natarov, D. M.; Benson, T. M.; Altıntaş, Ayhan; Sauleau, R.; Nosich, A. I.Using the field expansions in local coordinates and addition theorems for cylindrical functions, we consider the problem of the H-polarized plane wave scattered by a finite chain of circular wires. The absorption and scattering cross-sections are found numerically and plasmon and grating-type resonances are studied for the grids of silver nano-size wires. © 2010 IEEE.Item Open Access Lasing modes of infinite periodic chain of quantum wires(IEEE, 2009-06-07) Byelobrov, V. O.; Benson, T. M.; Sewell, P.; Altıntaş, Ayhan; Nosich, A. I.In this paper, we study the scattering and eigenvalue problems for a periodic open optical resonator that is an infinite chain of active circular cylindrical quantum wires standing in free space. The scattering problem is solved by the method of partial separation of variables. The eigenvalue problem differs from the first one by the absence of the incident field and presence of "active properties" of cylinders and yields the frequencies and thresholds of lasing. ©2009 IEEE.Item Open Access Lens or resonator? Electromagnetic behavior of an extended hemielliptic lens for a sub-millimeter-wave receiver(John Wiley & Sons, 2004) Boriskin, A. V.; Nosich, A. I.; Boriskina, S. V.; Benson, T. M.; Sewell, P.; Altintas, A.The behavior of a 2D model of an extended hemielliptic silicon lens of a size typical for THz applications is accurately studied for the case of a plane E-wave illumination. The full-wave analysis of the scattering problem is based on the Mutter's boundary integral-equations (MB1E) that are uniquely solvable. A Calerkin discretization scheme with a trigonometric basis leads tu a very efficient numerical algorithm. The numerical results related to the focusability of the lens versus its rear-side extension and the angle of the plane-wave incidence, as well as near-field profiles, demonstrate strong resonances. Such effects can change the principles of optimal design of lens-based receivers.Item Open Access Low-threshold Lasing eigenmodes of infinite periodic chain of quantum wires(Optical Society of America, 2010-10-26) Byelobrov, V.; Ctyroky, J.; Benson, T. M.; Sauleau, R.; Altintas, A.; Nosich, A. I.We study the lasing eigenvalue problems for a periodic open optical resonator made of an infinite grating of circular dielectric cylinders standing in free space, in the E- and H-polarization modes. If possessing a “negative-absorption” refractive index, such cylinders model a chain of quantum wires made of the gain material under pumping. The initial-guess values for the lasing frequencies are provided by the plane-wave scattering problems. We demonstrate a new effect: the existence of specific grating eigenmodes that have a low threshold of lasing even if the wires are optically very thin.Item Open Access The method of analytical regularization in the electromagnetic wave scattering by thin disks(Institution of Engineering and Technology, 2007) Balaban, M. V.; Nosich, A. I.; Altıntaş, Ayhan; Benson, T. M.We consider the problem of diffraction of an arbitrary electromagnetic wave by a thin disk made from different materials and located in free space. Here we imply a zero- thickness perfectly electrically conducting (PEC) disk, and also thin electrically resistive (ER) and dielectric disks whose thickness is much smaller than the disk radius and the free space wavelength, and also much smaller than the skin-layer depth in the ER disk case. The method used for the modeling is based on the integral equation (IE) technique and analytical regularization. Starting with Maxwell's equations, boundary conditions and the radiation condition at infinity we obtain a set of coupled dual IEs (DIEs) for the unknowns and then reduce this set of equations to the coupled IEs of the Fredholm second kind. To verify our results we calculate the far field characteristics in the case of the PEC disk with the incident field being the field of horizontal electrical dipole located on the disk axis.Item Open Access Plasmon and grid resonances in the electromagnetic scattering by finite grids of silver nanowires(IEEE, 2010) Natarov, D. M.; Benson, T. M.; Altıntaş, Ayhan; Sauleau, R.; Nosich, A. I.The problem of the H-polarized wave scattering by finite chains of circular nanowires is considered. A two-dimensional diffraction problem with rigorous boundary conditions is solved by partial separations of variables method using local polar coordinates of each scatterer. The obtained results demonstrate convergence of the algorithm and good agreement with data known for the conducting and dielectric cylinders. Plasmonic and grid resonances are found and calculated for grids from a big number of silver nanowires. This opens a way to the accurate numerical simulation of various finite configurations of wires met in today's nano and microsize photonic devices.Item Open Access Resonance lens antenna analysis for MM-wave applications(IEEE, 2004-06) Boriskin, A. V.; Nosich, A. I.; Boriskina, S. V.; Sewell, P.; Benson, T. M.; Altıntaş, AyhanWe report what is to our knowledge the first accurate theoretical investigation of the electromagnetic behavior of 2-D elliptical lenses of finite wavelength-scale size. The role of internal resonances in the focal domain formation is studied. A proposal of a narrow-band receiver based on a hemielliptic lens tuned to a resonance is discussed. Possible features of such a lens-coupled receiver are stability of the resonance field with respect to the angle of arrival of incident wave and several times greater values of the peak field intensity that may potentially lead to higher sensitivity and better scanning performance. In the analysis, we use the Muller boundary integral equation (BIE) technique. This full-wave mathematically rigorous method is combined with trigonometric Galerkin discretization to result in the efficient numerical solution for an arbitrary set of the electrical, geometrical, and material parameters. Numerical results are generated for a quartz elliptical lens (ε= 3.8) with dimensions typical to mm-wave radar applications. Near field analysis, lens-focusing properties and lens frequency-dependent performance are presented.Item Open Access Resonances in the electromagnetic scattering by very large finite-periodic grids of circular dielectric wires(IEEE, 2010-06) Natarov, D. M.; Benson, T. M.; Altıntaş, Ayhan; Sauleau, R.; Nosich, I.Diffraction of plane waves by infinite gratings is a classical research topic in the scattering theory. Using the Floquet theorem, one can reduce the infinite grating problem to the one-period problem. A characteristic feature of infinite-grating scattering is the drastic transformation of the scattering pattern and reflectance intensity if, in the process of changing the frequency or the angle of incidence, one of the Floquet harmonics is "passing over horizon." This phenomenon was first explained by Rayleigh [1] who studied theoretically the "anomalies" discovered experimentally by Wood [2]. In the simplest case of the normal incidence, these Rayleigh-Wood anomalies are observed if the period of the grating is multiple to the wavelength. © 2010 IEEE.