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標題: | 表面電漿金奈米結構之光操控研究 Light manipulation by gold nanobumps |
作者: | Chia-Min Chang 張家民 |
指導教授: | 蔡定平(Din Ping Tsai) |
關鍵字: | 表面電漿,光操控,奈米結構,奈米製程,表面光學, Surface plasmon,Optical manipulation,Nanostructures,Nanostructure fabrication,Optics at surfaces, |
出版年 : | 2011 |
學位: | 碩士 |
摘要: | 本論文研究在奈米光學領域中,光與表面奈米結構進行交互作用後的光學散射現象。當金屬薄膜與電磁波作用時會激發一種表面電荷震盪的物理現象─即表面電漿子(surface plasmon polariton),其激發的條件是由入射光波長、入射角度與偏振方向滿足表面電漿子色散關係所決定,此現象會在奈米金屬薄膜表面的近場範圍內產生光場的侷域化效應,並且可形成表面電漿子傳遞波。本研究基於此物理現象與概念,利用飛秒雷射製作特殊的金奈米凸起結構,由全反射式光學量測系統以衰逝全反射架構(Attenuated Total Reflection Configuration)量測金屬奈米結構與表面電漿波之間的散射影像,並探討其遠場散射行為與操控散射光之應用,藉此發展奈米尺度之三維光操控元件。
第一部分是針對金奈米凸起與表面電漿波作用後的光學散射行為做一系列研究,並分析不同聚焦平面之散射影像。在了解金奈米凸起對表面電漿波作用後的散射行為後,第二部分則研究由金奈米凸起排列的圓弧結構與表面電漿波交互作用之光散射現象,實驗觀察到於結構之上下空間的散射影像為兩狹長光臂包圍中央聚焦光點,此光點之強度半高寬為287 nm,此結果顯示可藉由排列奈米凸起將散射光重新疊加重建,而第三部分則藉由設計各種曲率圓弧結構研究如何控制此聚焦光點,實驗結果發現聚焦光點於空間的位置與圓弧曲率半徑呈正相關,表示當結構之曲率半徑愈大,其聚焦光點於上下空間距離結構表面的距離愈大。 綜合上述,本論文研究藉由改變金膜表面形貌,將表面電漿波重新耦合回遠場傳遞光,並提出利用圓弧結構於空間中重建聚焦光點,藉由控制圓弧之曲率半徑,改變聚焦光點出現於空間中不同高度位置,此研究結果對於未來奈米光子學元件發展上、三維光操控,積體光學元件以及表面電漿子學應用上提供一些可行的想法與雛型。 Surface plasmon polaritons (SPPs), which is quantization from surface collective electrons resonance, forms the surface plasma propagating wave. Surface plasmon wave can be modified by the artificial subwavelength structure on metal surface, such as plasmonic waveguide with the gold slots, plasmonics lens with grating, SPPs focusing by the quarter-circle, and squeezing near-field light by metallic nanoparticles. There are three basis mechanism processes to describe the SPP interaction with these subwavelength structures, namely SPP reflection, SPP transmission and scattering SPP in light. These researches open up the possibility to manipulate light and overcome the diffraction limit of the traditional optics. In this thesis, we study the interaction of SPPs with plasmonic structure composed of nanobumps on gold thin film. The SPPs of the gold film surface is launched by attenuation total internal refraction (ATIR) method with Nd:YAG laser (wavelength 532 nm). Total internal reflection fluorescence microscopy (TIRFM) system is employed to bring out the plasmonic mode of the structure. The nanobumps are directly fabricated on the 30 nm thick gold film by femtosecond laser illumination(wavelength 800 nm, pulse duration 140 fs, exposure time 30 ms), and the size of each nanobump is 300 nm for diameter and 16 nm for height. The subwavelength nanobumps of plasmonic structure are protuberance for scattering the SPPs wave. We find that the scattering light is restructured to spot by quarter circle structure and the property of spot depends on the geometry configuration of plasmonic structure. Furthermore, we also discover that the restructured spot of scattering light depends on curvature of structure. This research has potential to be applied in the area such as the integrated photonic circuit in the future. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/45408 |
全文授權: | 有償授權 |
顯示於系所單位: | 物理學系 |
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