Browsing by Author "Yang, Su-Lin"

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Analysis of effective plasma frequency in a superconducting photonic crystal
(2013-02-01)
Hu, Chung-An
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Wu, Chien-Jang
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Yang, Tzong-Jer
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Yang, Su-Lin
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電子物理學系
In this work, a theoretical analysis on the effective plasma frequency (EPF) for a one-dimensional superconductor dielectric photonic crystal is made. First, the EPF is extracted from the first photonic band calculated within the framework of transfer matrix method together with Bloch theorem in a periodic multilayer structure. We investigate the EPF as a function of the filling factor and the permittivity of the dielectric layer, and the operating temperature as well. Then, the EPF is comparatively studied by the analytical expression derived from the effective medium theory. It is found that both results are in fairly good agreement. (C) 2013 Optical Society of America
Analysis of optical properties in cylindrical dielectric photonic crystal
(2013-03-15)
Hu, Chung-An
;
Wu, Chien-Jang
;
Yang, Tzong-Jer
;
Yang, Su-Lin
;
電子物理學系
In this work, theoretical formulas for the H-polarization electromagnetic propagation in a cylindrical multilayer structure (CMS) are given. The relationships between two modes, H- and E-polarization are pointed out. With the derived formulae, we present the numerical results for three model structures such as the single cylindrical interface, the single cylindrical slab, and the cylindrical photonic crystal (CPC). In the single cylindrical interface, it is found that there exists a Brewster starting radius at which a minimum reflectance is attained in H-polarization. In the single cylindrical slab, the result illustrates that the reflectance response in the wavelength domain contains the oscillating and nonoscillating regions. As for the CPC, we find the PBG structure at zero azimuthal mode number is very similar to that of planar photonic crystal. The PBG, however, can be strongly influenced by increasing the azimuthal mode number in a CPC. (C) 2012 Elsevier B.V. All ights reserved.
Effect of photonic crystal band gap on rotation of hollow oval Te rods in triangular lattice
(2006-09-01)
Chang, Kuo-Pin
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Yang, Su-Lin
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電子物理學系
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Department of Electrophysics
The band structures and field patterns of two-dimensional (2D) triangular photonic crystals with hollow tellurium (Te) rods are calculated using the plane-wave method. Inner-rod and whole-rod rotations are considered to investigate how the rotational and structural symmetries affect E- and H-polarization modes. It is indicated that the H-polarization modes are strongly affected by the shape and interaction between the fields of the rods. In addition, the effect of rotational symmetry on H-polarization modes must be considered when whole rods are rotated. The E-polarization modes for both types of rotations are strongly related to the shape of the rods. Moreover, H-polarization modes determine the absolute photonic band gap (PBG) width when whole rods are rotated, while E-polarization modes determine the absolute PBG width when inner rods are rotated.
Effects of superconducting film on the defect mode in dielectric photonic crystal heterostructure
(2013-03-01)
Hu, Chung-An
;
Liu, Jia-Wei
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Wu, Chien-Jang
;
Yang, Tzong-Jer
;
Yang, Su-Lin
Effects of superconducting thin film on the defect mode in a dielectric photonic crystal heterostructure (PCH) are theoretically investigated. The considered structure is (12)S-N(21)(N), in which both layers 1 and 2 are dielectrics, layer S is a high-temperature superconducting layer, and N is the stack number. The defect mode is analyzed based on the transmission spectrum calculated by using the transfer matrix method. It is found that, in the normal incidence, the defect mode existing in the host PCH of (12)(N)(21)(N) will be blue-shifted as the thickness of layer S increases. In addition, the defect mode is also blue-shifted for both TE and TM modes in the case of oblique incidence. The embedded superconducting thin film plays the role of tuning agent for the defect mode of PCH. As a result, the proposed structure can be designed as a tunable narrowband transmission filter which could be of technical use in the optoelectronic applications. (c) 2013 Elsevier Ltd. All rights reserved.
Variation in the Absolute Photonic Band Gap of Rods Ranging from Square to Octagonal in Square Lattices
(2011-07-01)
Hu, Chung-An
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Chang, Kuo-Pin
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Yang, Su-Lin
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Shen, Lin Fang
;
Wu, Jin-Jei
The band structures and field patterns of dielectric rods in square lattices are calculated using the plane-wave method. The rods with various cross-sectional shapes from square to octagonal at a fixed filling-factor are constructed to assess the geometry effect of photonic crystals to their band gap properties. Analytical results indicate that the corner profiles of rods significantly affect the E- and H-polarization bands in resonance frequency and field distribution. The absolute photonic band gap is closed in the square lattice when square dielectric rods are replaced with octagonal dielectric rods. (C) 2011 The Japan Society of Applied Physics