The optical fibers, coated with plasmonic active metal films, represent the simple and unpretentious sensors, potentially useful for measurements of physical or chemical quantities and wide range of analytical application. All fiber-based plasmonic sensors operate on the same physical principle based on changes in the position of the plasmon absorption peak induced by a variation of surrounding medium refractive index. However, the observed spectral differences are often weak, and thus an enhancement of sensor sensitivity is strongly required. In this paper, we propose the immobilization of gold nanoparticles with sharp edges on the thin gold layer, deposited on the multimode fiber surface for improvement of the sensor functionality. The morphological and compositional changes in the gold covered fiber surface were determined by using the atomic force microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy methods. As a result of gold nanoparticles immobilization, the pronounced plasmon energy concentration near the fiber surface occurred, thus enhancing the response of the proposed hybrid plasmonic system to the variation of ambient refractive index. The position of plasmon absorption in the case of the created plasmonic structure was shown to be more sensitive to the changes in the surrounding medium in comparison with the standard sensors based on the bare gold layer.

中文翻译：

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通过金纳米粒子的接枝提高表面等离子纤维传感器的灵敏度

涂有等离激元活性金属膜的光纤代表了简单而朴实的传感器，可能对物理或化学量的测量以及广泛的分析应用有用。所有基于光纤的等离子体传感器都基于相同的物理原理，基于由周围介质折射率的变化引起的等离子体吸收峰的位置变化。然而，观察到的光谱差异通常较弱，因此强烈需要增强传感器灵敏度。在本文中，我们提出将金锋利的金纳米颗粒固定在薄金层上，并沉积在多模光纤表面上，以改善传感器的功能。通过使用原子力显微镜，扫描电子显微镜和能量色散X射线光谱法测定了金包被的纤维表面的形态和组成变化。由于金纳米颗粒的固定化，在纤维表面附近出现了明显的等离激元能量集中，从而增强了所提出的混合等离激元系统对环境折射率变化的响应。与基于裸金层的标准传感器相比，在创建的等离激元结构的情况下，等离激元吸收的位置对周围介质的变化更敏感。在纤维表面附近出现明显的等离激元能量集中，从而增强了所提出的混合等离激元系统对环境折射率变化的响应。与基于裸金层的标准传感器相比，在创建的等离激元结构的情况下，等离激元吸收的位置对周围介质的变化更敏感。在纤维表面附近出现明显的等离激元能量集中，从而增强了所提出的混合等离激元系统对环境折射率变化的响应。与基于裸金层的标准传感器相比，在创建的等离激元结构的情况下，等离激元吸收的位置对周围介质的变化更敏感。