| Summary: | 碩士 === 國立海洋大學 === 光電科學研究所 === 89 === The study of light propagating across sub-micron slits is not only a theoretical electromagnetic wave problem, but also has practical applications, for example, the “near-field scanner”. The scanner has super optical resolution by using a sub-micron slit to generate evanescent wave. The major advantage of the scanner is to get the optical image in real time. The resolution is closely related to the width of silt in the scanner structure. Hence, understanding the propagation behavior of the light across such sub-micron silts is essential. In our experiment, we set up a scanning near-field spectroscopy to study the slits. By changing the incident wavelength, we can observe the effect of wavelength for different slit widths. In addition, we have altered the control circuits to add the capability for measuring the propagation of the light by our near-field spectroscopy. For comparisons with the electromagnetic theory, we have also developed the “finite-difference time-domain” method to simulate the propagation of light and the images of evanescent wave distributions across the slits. The simulations are consistent with the experimental results and give more insight about the near-field scanner.
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