Kiyotoshi Yasumoto

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An efficient and accurate method to the problem of planewave scattering from periodic arrays of two circular-cylinders per unit cell is presented. The scattered fields are calculated using the lattice sums characterizing a periodic arrangement of scatterers and the aggregate T -matrix for the isolated two-cylinders system in free space. The cylinders may be(More)
A very efficient and accurate method to characterize two-dimensional (2-D) electromagnetic scattering from multilayered periodic arrays of parallel circular cylinders is presented, using the lattice sums technique, the aggregate T-matrix algorithm, and the generalized reflection and transmission matrices for a layered system. The method is quite general and(More)
A very efficient and accurate method to characterize the electromagnetic scattering from periodic arrays of 2D composite cylindrical objects with eccentric cylindrical inclusions is presented, using the lattice sums formula and the aggregate T-matrix. The dielectric host cylinder per unit cell can contain two or more eccentric cylindrical inclusions, which(More)
The Fourier series expansion method is a useful tool to approach the problems of discontinuities in optical waveguides, and it applies to analyze the Floquet-modes of photonic crystal waveguides. This paper shows that the Floquet-mode calculation with large truncation order is limited and explains the reason. Furthermore, two techniques of the formulation(More)
A self-contained coupled-mode theory for the coupled two asymmetric photonic crystal waveguides (PCWs) is presented. The first-order coupled-mode equations are derived under a weak coupling assumption. The coupling coefficients are obtained systematically by a matrix calculus using the modal solutions of each PCW in isolation. The coupled-mode equations are(More)
A numerical approach for analyzing two-dimensional photonic crystal circuits are proposed. The method uses a technique of concatenation between the local normal modes and the Floquet modes through the scattering matrices based on the Fourier mode analysis. Numerical examples for several circuit components are presented for demonstrating the effectiveness of(More)
A numerical method in the frequency domain is developed for analyzing three-dimensional gratings using the concept of a double-periodic magnetodielectric layer. The method is based on the three-dimensional volume integral equations for the equivalent electric and magnetic polarization currents of the assumed periodic medium. The integral equations are(More)
The two-dimensional scattering of a Gaussian beam by a periodic array of circular cylinders is studied. The incident Gaussian beam is expressed as a superposition of plane waves of different amplitudes and different incident angles, using the plane-wave spectrum technique based on Fourier optics. For each plane wave, the scattered field is calculated with(More)
A rigorous semi-analytical approach for analyzing the guidance and scattering of electromagnetic waves by layered cylindrical arrays of circular rods is presented. The method is based on the vector wave formulation and uses the T-matrix of a single circular rod in isolation, the reflection and transmission matrices of a cylindrical array expressed in terms(More)