利用週期性奈米結構激發橫向電波之表面電漿振盪

等效導納軌跡在膜層分析與設計當中是一種相當方便且精確的理論，在Kretschman組態下介質/銀/空氣之架構為激發縱向電波表面電漿振盪基本的例子，而在激發表面電漿振盪的入射角之金屬層等效導納軌跡由正虛軸往正實軸附近繞，因此在本論文中，由斜向S型奈米結構或者高低折射率材料堆疊出之週期性奈米結構，模擬製鍍在金屬性良好的均向金屬薄膜上，在Kretschman組態下，且由固定波長之TE電磁波入射，可產生與TM波表面電漿振盪類似的等效導納軌跡，分析膜層中之電場分布情形藉以確認為TE波表面電漿振盪。在實驗上，利用電子槍的製程方式，以二氧化矽（SiO2）為斜向S型奈米結構之材料，製鍍在均向鋁（Al）薄膜，另外以二氧化鈦（TiO2）為高折射率材料，二氧化矽為低折射率材料，均向銀（Ag）薄膜下製鍍週期性奈米結構，製鍍出稜鏡/銀/斜向S型奈米結構/空氣以及稜鏡/銀/均向週期介質對稱膜堆/空氣的組態，在He-Ne雷射（波長為632.8奈米）入射電磁波下，觀察在不同週期薄膜的TE波入射角頻譜，並利用電場分析，判斷其吸收波峰為表面電漿振盪或者波導，以確認表面電漿振盪激發的位置。

關鍵字

等效導納；表面電漿；週期性奈米結構

並列摘要

The effective admittance is a convenient and exact theory to analyze or design thin films. For instance, the system medium/Ag/air in Kretschman configuration is a simple example which excites TM-mode surface plasmon resonance (SPR). At the resonance angle, the admittance locus of the metal layer starts at the positive imaginary axis and ends nearby the positive real index of incident medium. In this study, an s-shape nanostructure or a multilayer of symmetric film stack underneath the metal film in Kretschmann configuration has the similar effect index in TE-mode as the TM-mode SPR. The TE-mode SPR is demonstrated by analyzing the electric field distribution at the absorptance peaks in the angular apectrum. In experiment, all materials are evaporated on the BK7 substrate by electron-beam system. SiO2 material is used to fabricate a 3-period anisotropic s-shape film in BK7/Al/s-shape nanostructure/air system. Besides, TiO2 and SiO2 materials are used as evaporation sources to fabricate 1 to 4-period multilayer of symmetric film stack in BK7/Ag/periodic nanostructures/air systems. The absorptance angular spectrum is measured and calculated in attenuated total reflection (ATR) system with He-Ne laser (632.8nm). When absorptance peak happens, the analysis for electric field distribution at the absorptance peaks is used to demonstrate the SPR.

並列關鍵字

effective admittance ； surface plasmon ； periodic nanostructure

參考文獻

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[5] I.J. Hodgkinson, “The change in thickness and other optical properties of ultraviolet irradiated silicon oxide films,” Applied Optics 9 (7), pp. 1577-1586 (1970).

structure of SiO2 films prepared by ion-beam sputtering,” Thin Solid Films 289 (1-2), pp. 84-89 (1996).

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利用週期性奈米結構激發橫向電波之表面電漿振盪

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