Browsing by Author "Wu, Chien-Jang"

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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
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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.
Effects of superconducting film on the defect mode in dielectric photonic crystal heterostructure
(2013-03-01)
Hu, Chung-An
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Liu, Jia-Wei
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Wu, Chien-Jang
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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.
Optical properties of a superconducting annular periodic multilayer structure
(2009-11-01)
Chen, Mei-Soong
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Wu, Chien-Jang
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Yang, Tzong-Jer
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電子物理學系
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Department of Electrophysics
The optical properties of a superconducting annular Bragg reflector (SABR) are theoretically investigated based on the transfer matrix method for the cylindrical waves. For TM wave at an azimuthal mode number, in >= 1, it is found that there exist some novelties compared with the usual superconducting planar Bragg reflector (SPBR). An additional high-reflectance band is seen and some reflection dips near the threshold wavelength of a superconductor are generated as well. These two special results arising from the higher order azimuthal mode of the cylindrical waves are not found in the SPBR. The results suggest that the SABR could be used to design a narrowband transmission Filter or an annular resonator without introducing any physical defect layer in the structure. (C) 2009 Elsevier Ltd. All rights reserved.
Wave properties of an annular periodic multilayer structure containing the single-negative materials
(2009-09-21)
Chen, Mei-Soong
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Wu, Chien-Jang
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Yang, Tzong-Jer
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電子物理學系
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Department of Electrophysics
The optical properties of an annular periodic multilayer structure containing two kinds of single-negative materials are theoretically investigated based on the transfer matrix method of the cylindrical waves. At the azimuthal mode number m >= 1 and near the magnetic plasma frequency and the electronic plasma frequency for the TE wave and TM wave, respectively. we find that there is an additional high-reflectance band and some reflection dips exist when the plasma frequency is located in the photonic band gap. These two special features arising from the higher order azimuthal mode of the cylindrical waves are not seen in the planar one-dimensional Bragg reflector consisting of the single-negative materials. Such filtering responses provide a feasible way of designing a narrowband resonator without physically introducing any defect layer in the structure. (C) 2009 Elsevier B.V. All rights reserved.