Browsing by Subject "Finite-difference time-domain (FDTD) methods"
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Item Unknown 2D anisotropic photonic crystals of hollow semiconductor nanorod with liquid crystals(2013) Karaomerlioglu F.; Şimsek, Şevket; Mamedov, Amirullah M.; Özbay, EkmelPhotonic crystals (PCs) have many applications in order to control light-wave propagation. A novel type of two-dimensional anisotropic PC is investigated band gap and optical properties as a hollow semiconductor nanorod with nematicliquid crystals (LC). The PC structure composed of an anisotropic nematicLC in semiconductor square hollow nanorod is designed using the plane wave expansion (PWE) method and finite-difference time-domain (FDTD) method. It has been used 5CB (4-pentyl-4'-cyanobiphenyl) as LC core, and Tellurium (Te) as square hollow nanorod material.The PC with hollow Tenanorod with nematicLC is compared with the PC with solid Tenanorodand the PC with hollow Tenanorod. © (2013) Trans Tech Publications, Switzerland.Item Unknown Broadband circular polarizer based on high-contrast gratings(Optical Society of America, 2012-05-30) Mutlu, M.; Akosman, A. E.; Özbay, EkmelA circular polarizer, which is composed of periodic and two-dimensional dielectric high-contrast gratings, is designed theoretically such that a unity conversion efficiency is achieved at λ0 = 1.55 μm. The operation is obtained by the achievement of the simultaneous unity transmission of transverse magnetic and transverse electric waves with a phase difference of π/2, meaning that an optimized geometrical anisotropy is accomplished. By the utilization of the rigorous coupled-wave analysis and finite-difference time-domain methods, it is shown that a percent bandwidth of ∼50% can be achieved when the operation bandwidth is defined as the wavelengths for which the conversion efficiency exceeds 0.9.