Study on the thermal expansion coefficients of holographic gratings by heterodyne interferometry
碩士 === 元智大學 === 光電工程學系 === 104 === In this study, the thermal-optical properties of holographic gratings were measured by using total-internal reflection (TIR) heterodyne interferometry. The grating pitch changes with the variation in the temperature of the holographic grating, leading to variation...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2016
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| Online Access: | http://ndltd.ncl.edu.tw/handle/77003037014556379582 |
| Summary: | 碩士 === 元智大學 === 光電工程學系 === 104 === In this study, the thermal-optical properties of holographic gratings were measured by using total-internal reflection (TIR) heterodyne interferometry. The grating pitch changes with the variation in the temperature of the holographic grating, leading to variation of the diffraction angle. The phase difference between the p- and s- polarizations resulting from the diffraction angle variation of the holographic diffraction grating at various temperatures can be measured. Based on this property, the diffraction angle variation measurement can be used to determine the variation of the grating pitch, thus enabling the effective thermal expansion coefficients (ETEC) of the diffraction grating to be obtained. Our results showed that the holographic material exhibited a smaller thermal expansion coefficient with longer exposure time than those materials with short exposure times. The best resolution of the proposed method is better than 1.6165*10-3/℃ and the practical ETEC error under the precision measurement conditions can reach to 0.1071*10-3/℃.
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