Browsing by Author "Chang, Hung-chun"

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A High-Accuracy Multidomain Legendre Pseudospectral Frequency-Domain Method With Penalty Scheme for Solving Scattering and Coupling Problems of Nano-Cylinders
(2013-03-01)
Wang, Chih-Yu
;
Chung, Shih-Yung
;
Teng, Chun-Hao
;
Wang, Juen-Kai
;
Chen, Chung-Ping
A new multidomain pseudospectral frequency-domain (PSFD) method based on the Legendre polynomials with penalty scheme is developed for numerically modeling electromagnetic wave scattering problems. The primary aim of the proposed method is to more accurately analyzing scattering and coupling problems in plasmonics, in which optical waves interact with nanometer-sized metallic structures. Using light scattering by a silver circular cylinder as a first example, the formulated method is demonstrated to achieve numerical accuracy in near-field calculations on the order of 10(-9) with respect to a unity field strength of the incident wave with excellent exponentially convergent behavior in numerical accuracy. Then, scattering by a dielectric square cylinder and that by several coupled metallic structures involving circular cylinders, square cylinders, or dielectric coated cylinders are examined to provide high-accuracy coupled near-field results.
High-Accuracy Waveguide Leaky-Mode Analysis Using a Multidomain Pseudospectral Frequency-Domain Method Incorporated With Stretched Coordinate PML
(2013-07-15)
Wang, Chih-Yu
;
Liu, Hsuan-Hao
;
Chung, Shih-Yung
;
Teng, Chun-Hao
;
Chen, Chung-Ping
A recently developed pseudospectral frequency-domain (PSFD) method employing a penalty scheme is further incorporated with stretched coordinate perfectly matched layers (PMLs) in order to solve waveguide leaky modes. Several standard leaky-mode slab and circular waveguides, including the W-type and M-type ones, are examined first by solving their complex effective indexes and field profiles, showing that the PSFD method achieves computational accuracy on the order of. Then, this high-accuracy solver is used to analyze waveguide structures with more complicated geometries, such as the leaky six-air-hole fiber, for which self convergence of accuracy in calculated effective indexes is demonstrated to be on the orders of, and two rectilineal waveguides with sharp corners, i.e., the rib waveguide and the photonic wire. Comparison of the PSFD method obtained results for these more complicated waveguide structures with those from other methods in the literature is presented and discussed.
Investigation of Nanoelectromagnetics Problems Using the Multidomain Legendre Pseudospectral Time-Domain Method
(2012)
Chang, Hung-chun
;
Chung, Shih-Yung
;
Wang, Chih-Yu
;
Teng, Chun-Hao
;
Wang, Juen-Kai
Nanoelectromagnetics problems in nanophotonics and plasmonics in the optical-wavelength regime are concerned in this paper. Very often such problems demand more accurate electromagnetic computation and analysis. A multidomain Legendre pseudospectral time-domain (PSTD) method recently developed and demonstrated to provide high numerical accuracy is utilized to study light interaction with sub-wavelength three-dimensional plasmonic structures and associated plasmonic resonances. With the multidomain technique, the simulation region is partitioned into curvilinear hexahedral subdomains with better fitting to the structural shapes and material interfaces so as to achieve high-accuracy near-field calculations. Light scattering by multiple plasmonic nanospheres and light transmission through a metallic thin film perforated with periodic apertures are investigated with the PSTD analysis.
Solving Optical Waveguide Leaky Modes Using a Multidomain Legendre Pseudospectral Frequency-Domain Method
(2013)
Wang, Chih-Yu
;
Chung, Shih-Yung
;
Teng, Chun-Hao
;
Chen, Chung-Ping
;
Chang, Hung-chun
A Legendre pseudospectral frequency-domain (PSFD) method incorporated with stretched coordinate perfectly matched layers (PMLs) and a multidomain technique is established for solving optical waveguide leaky modes. A recently developed penalty scheme is employed to assure numerical accuracy. This high-accuracy solver is used to analyze a leaky six-air-hole microstructured fiber, for which self convergence of accuracy in calculated effective indexes is demonstrated to be on the orders of 10(-14). Then, the photonic wire is analyzed and the comparison with the analysis results from other methods is discussed.