| Summary: | 碩士 === 臺灣大學 === 光電工程學研究所 === 95 === The objective of this thesis is to investigate the surface plasmon polariton (SPP) existing on the metal surface for inducing extraordinary transmission and enhancing the spontaneous emission rate by using the finite-difference frequency domain (FDFD) method. The FDFD method is superior to the finite-difference frequency-domain method in treating the dispersive materials, suck as metal. However, more computer memory is needed for FDFD. We match the boundary conditions to take care of the interface between the metal and the dielectric in the FDFD method. Thus the SP wave distribution on the metal surface can be accurately simulated.
In the simulation process, a unit cell of the periodic structure is first adopted as our simulation domain. We use the TE plane wave incidence on the rectangular metal (silver) structure to observe the surface plasmon distribution and the metal loss effect, and to investigate the relationship between the SPP modes and the width and thickness of the metal. Next, we use a magnetic current line source or electric dipole source in place of the plane wave to examine the coupling between the SPP and a point source. When we get the results of increasing spontaneous emission rate and optical transmission, we expand the metal structure domain to fit the real situation. According to the simulation results, the surface plasma waves on the periodic metal structure indeed can enhance the emission rate of these two kinds of sources.
For the more realistic situation, we use 800 magnetic current line sources or electric dipole sources with random phases and distribute them along a line. These sources may represent an active layer for lighting. After one hundred statistical realizations, we find that the spontaneous emission rate and optical transmission can be enhanced for both kinds of sources by the periodic metal structure under the suitable conditions.
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