週期性銀奈米陣列結構於螢光增益與螢光亮度對比之探討

Enhancement of Fluorecent Emission and Contrast From Periodical Array of Silver Nanostructures

戴琨育(Kun-Yu Tai)

指導教授 ： 甘宏志

國立中正大學/理學院/物理學系/碩士(2012年)

摘要

螢光成像已經被廣泛應用於生物學或醫學檢測。利用金屬奈米粒子或週期性金屬奈米結構之表面電漿現象用以提高螢光檢測靈敏度的是最近極為熱門的研究課題。當金屬奈米粒子或奈米結構被入射光所照射，所激發表面電漿子振盪在其表面附近產生局域性電場增益。利用金屬表面增益螢光的原理及再將螢光分子放在金屬表面附近但不直接接觸到金屬表面，藉由近場增益進而造成螢光增益。我們使用電子束微影技術在ITO基板上製作週期性銀奈米陣列結構，並利用共軛聚焦顯微鏡測量所塗佈在銀結構上的所發射之螢光信號之增益。在本論文裡，我們探討其螢光增益於金屬奈米陣列結構週期之關係，以及激發光入射方向對螢光亮度對比度之影響。我們觀察到在週期350nm的銀奈米結構所產生的螢光最大增益約90倍，並藉由改變激發光源的方向，增強了奈米陣列結構相對於平滑銀膜之間的螢光亮度對比度約500倍。

關鍵字

表面電漿 ； 螢光增益 ； 銀奈米陣列結構

並列摘要

Fluorescent imaging has been widely used in biological or medical detections. Recently there has been strong interest in applications of surface plasmon on metal nanoparticles or periodic metal nanostructures to enhance the sensitivity of fluorescent detection. When metallic nanoparticles or nanostructures are illuminated by an incident light, their plasmonic response results in enhancement of local fields near the surface. Fluorophores placed near but not in direct contact with the metal surface will be excited with this enhanced near field, thus produce enhanced fluorescent emission. We fabricated arrays of periodic Ag nanostructure on ITO-glass substrate with electron beam lithography, and measured the fluorescent emission from the fluorophores coated on patterned area and that from the unpatterned area with confocal microscopy.Here,we investigate the fluorescence enhancement from the surface plasmon excited on periodic metal nano-array structure with varying periodicity and how the incident orientation of the excitation light effects the fluorecent constrast of the sample.We observed an over-90 time enhancement in fluorescent emission from periodic Ag nanostructures, with the optimum occuring at periodicity around 350nm.By changing the direction of excitation illumination, we substantially increased the fluorescent contrast between the nano-array and the flat Ag surface, we observed an over-500 enhancement in time fluorescent contrast.

並列關鍵字

Surface Plasmon ； Fluorescence Enhancement ； Array of Silver Nanostructures

參考文獻

[1] H. Raether, Surface Plasmons (Springer , New York,1988).

[3] D. A. Schultz, Current Opinion in Biotechnology 14,13 (2003).

[5] A. Schonle and S. W. Hell, “heating by absorption in the focus of an objective lens”, Opt. Lett. 23, 325-327 (1998)

[9]F.Yu, Surface Plasmon Fluorescence Spectroscopy and Surface Plasmon Diffraction in Biomolecular Interaction Studies, Mainz, (2004)

[10]E. Kretschmann, H. Raether, Z. Naturforsch. A 23 2135.A. (1968)