Design of a flat focusing mirror without an optical axis based on a periodic sub-wavelength grating on an optical waveguide
| Autor: | Juei-Hung Tsai, 蔡睿鴻 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 Sub-wavelength grating waveguide structure is proposed to realize a flat focusing mirror, which can focus on a Gaussian beam in reflection. The principle of the design is to calculate the reflection phase of the plane wave incident at different angles. When the incident light angle is inversely proportional to the lateral displacement (the reflection phase versus the first differential of the angle), it could be predicted that the Gaussian beam can be focused on the reflective surface at this angular range. In particular, the flat-plate focusing mirror utilizes a periodic structure to modulate the phase changes of the angle, rather than the structure in the modulation space to achieve a corresponding phase change. Different from the flat-focusing elements disclosed in the past, such as high contrast sub-wavelength gratings and Metasurface, the flat focusing mirror designed can be focused at any point without optical axis. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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