| Summary: | 碩士 === 清雲科技大學 === 電子工程系所 === 96 === In this dissertation, we have undertaken a theoretical approach to the complex problem of modeling the flour of electromagnetic waves in photonic crystals and in near-field optics. Our focus is to address the feasibility of using the exciting phenomena of photonic crystal and near-field optics in actual applications, such as photonic crystal fiber(PCF) and silver-shell nanocylinders. Firstly, a kind of highly birefrigent index guiding elliptical air-hole PCF by the finite element method is analyzed theoretically. Two-fold rotational symmetry was introduced into the fiber structure by creating a regular array of air-holes of two different sizes in its cladding. The degeneracy of two orthogonal polarized-modes of the fundamental mode is removed. In this work, the influence of the wavelengths, aspect ratio of the elliptical air-hole sizes, effective area and the numbers of air-hole rings upon the modal birefringence is analyzed. Our suggested structures can show that the birefringence can be as high as 1.1294×10-2, which is higher than the birefringence obtained from conventional step-index fiber (5×10-4), circular air-holes photonic crystal fiber(3.7×10-3), and elliptical hollow photonic crystal fiber (2.35×10-3). Secondary, we compared the near-field optical response of silver-shell nanocylinders with silver nanocylinders , we found that the performance of silver-shell nanocylinders is superior to that of silver nanocylinders. The surface plasmon resonance has red-shift for silver-shell nanocylinders system by tuning the radius of air-hole in nanocylinders. The resonance wavelength and local-field enhancement are nearly proportional to the radius of air-hole in nanocylinders. It has vast potential to become an important application for biosensor and plasmonic devices.
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