Wavelength tunable surface plasmon resonance-enhanced optical transmission through a chirped diffraction grating.
Wavelength tunable surface plasmon resonance-enhanced optical transmission through a chirped diffraction grating.
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DOI：
10.1021/ac100497w
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发表时间：
2010-05
影响因子：
7.4
通讯作者：
Wei-Hsun Yeh;Justin A. Kleingartner;A. Hillier
中科院分区：
文献类型：
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作者：
Wei-Hsun Yeh;Justin A. Kleingartner;A. Hillier
报道了一种用作表面等离子体增强光传输衬底的啁啾衍射栅的构造和测试。这种光栅具有沿其表面的节距和幅度的空间变化。它是通过等离子体氧化弯曲的聚二甲氧基硅烷薄片产生的，导致聚合物表面不均匀的屈曲。这个表面的镀金复制品引起了光学响应，包括一系列分布在可见光光谱上的窄的、增强的透射峰。这些透射峰的位置和大小沿着光栅的表面变化，并且与表面等离子体通过耦合到一个或多个光栅的衍射级而在金膜中被激发的条件一致。利用光学衍射、原子力显微镜和垂直入射光学透射法进行了一系列测量，以比较光栅的拓扑结构和相应的光学响应。此外，通过在光栅表面沉积一层薄的氧化硅薄膜来确定薄介质涂层对传输响应的影响。镀膜后，在透射峰中观察到波长移动，移位的大小是薄膜厚度、局部光栅结构和与每个峰相关联的衍射级的函数。这些结果说明了这种表面作为一个信息丰富的光学传感器的能力，其特性可以通过控制局部栅拓扑来调节。
We report the construction and testing of a chirped diffraction grating, which serves as a substrate for surface plasmon-enhanced optical transmission. This grating possesses a spatial variation in both pitch and amplitude along its surface. It was created by plasma oxidation of a curved poly(dimethoxysilane) sheet, which resulted in nonuniform buckling along the polymer surface. A gold-coated replica of this surface elicited an optical response that consisted of a series of narrow, enhanced transmission peaks spread over the visible spectrum. The location and magnitude of these transmission peaks varied along the surface of the grating and coincided with conditions where surface plasmons were excited in the gold film via coupling to one or more of the grating's diffracted orders. A series of measurements were carried out using optical diffraction, atomic force microscopy, and normal incidence optical transmission to compare the grating topology to the corresponding optical response. In addition, the impact of a thin dielectric coating on the transmission response was determined by depositing a thin silicon oxide film over the grating surface. After coating, wavelength shifts were observed in the transmission peaks, with the magnitude of the shifts being a function of the film thickness, the local grating structure, and the diffracted order associated with each peak. These results illustrate the ability of this surface to serve as an information-rich optical sensor whose properties can be tuned by control of the local grating topology.