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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/1706


    Title: 紅外波段分光之全像集光器應用;Holograms for dividing infrared spectrum in solar concentrator application
    Authors: 吳琮凱;Tsung-Kai Wu
    Contributors: 光機電工程研究所
    Keywords: 全像光學元件;分光;重鉻酸明膠;繞射波段調制;hologram optical element;spectrum dividing;dichromated gelatin;diffraction wave band modulate
    Date: 2009-07-31
    Issue Date: 2009-09-21 09:58:04 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 本論文主要研究太陽能應用中分光器的設計,利用全像光學元件具有繞射分光之特性,透過短波長曝光長波長重建之技術,有效地繞射太陽光中紅外波段光,進而達到分光的效果。 根據全像記錄材料特性的不同,其應用的範圍和需求也有所不同。本論文中使用之感光記錄材料為重鉻酸明膠 (DCG),其具有高繞射效率、高解析度、高調制折射率、低訊噪比和低吸收等優點,在全像分光元件製作中為最合適的記錄材料。並利用改變拍攝幾何架構之參數,即改變記錄光角度,可改變繞射波段之中心波長。 由文獻得知,繞射效率的高低與調制折射率有關。故為了拍攝出理想中之分光全像光學元件,如何找出最佳曝光時間點和實驗幾何架構的參數設計,即成為本論文主要研究的重點。 利用理論推導和量測證實,實驗所拍攝出之全像元件在近紅外波段之繞射效率峰值可達到70%,近紅外波段平均繞射效率可達到40%,理論與實驗之平均繞射波段中心波長偏移量約為140 nm。 本論文利用改變全像拍攝幾何架構的方式,可以將繞射波段有效地紅移至近外紅波段,未來可搭配高集光倍率之集光器(菲涅爾透鏡),將可見光和紅外光分開聚焦並轉換,有效地提高光電、光熱之轉換效率。 In this thesis, the principle is based on Spectrum-Dividing Technology for solar application. By using hologram optical element which can record interference signals by short wavelength light, and change incident angle of record light, long wavelength light can be reconstructed. The infrared part of sunlight can be diffracted effectively. According to the difference from the characteristics of hologram optical elements (HOE), the application scope and requirement change enormously. In this thesis we choose dichromated gelatin between the materials with high diffraction efficiency, high resolution, high refractive index modulation, low signal to noise ratio and low absorption. Furthermore, if we change the parameters of system configuration, i.e. the incident angle of record light, the diffraction wave band will change relatively. The literature shows that the higher refractive index modulation causes the higher diffraction efficiency. In order to get high diffraction efficiency and diffraction wave band in infrared, finding the best exposure time as well as optimized parameters of system configuration are important in this thesis. The experiment results demonstrate that the maximum of diffraction efficiency in infrared can achieved about 70%, the average of diffraction efficiency in infrared is about 40% and the average central wavelength deviation of diffractive wave band between theoretical values and experiment results is about 140 nm. In the future, hologram can combine with Fresnel lens such that visible light and infrared can be separated and focused at two points respectively, and collecting them by using photoelectric and photothermal systems which can increase solar conversion efficiency.
    Appears in Collections:[光機電工程研究所 ] 博碩士論文

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