Optimal Design for U-bent Fiber-optic LSPR Sensor Probes
Optimal Design for U-bent Fiber-optic LSPR Sensor Probes
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DOI：
10.1007/s11468-013-9618-7
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发表时间：
2014-04-01
期刊：
影响因子：
3
通讯作者：
Mukherji, Soumyo
中科院分区：
文献类型：
--
作者：
Satija, Jitendra;Punjabi, Nirmal Suresh;Mukherji, Soumyo
基于局域表面等离子体共振（LSPR）的光纤探针的折射率（RI）灵敏度取决于金纳米颗粒（GNP）的表面覆盖率、光纤芯直径和探针几何形状。对于U形弯曲LSPR光纤探针，其吸收灵敏度比直探针高出一个数量级，弯曲直径和探针长度也可能对灵敏度有显着影响。本研究的U型弯曲光纤LSPR探针的目的是优化这些参数，以获得尽可能高的RI灵敏度。RI灵敏度在2 - 22%的范围内作为GNP的表面覆盖度的函数线性增加。由200 μ m、400 μ m和600 μ m纤芯直径制成的U形弯曲光纤探头显示最佳弯曲直径值为-1.4 mm。此外，RI灵敏度几乎相同，与纤芯直径无关，这表明在选择光纤方面具有灵活性，并且易于光耦合。在弯曲区域之前和之后的探针的长度对RI灵敏度的影响显著较小，从而允许这些探针的小型化。除了这些实验研究，我们提出了一个理论分析，以了解GNP的倏逝波吸收率和光纤中的折射损耗，由于GNP，对RI的灵敏度的相对贡献。
The refractive index (RI) sensitivity of a localized surface plasmon resonance (LSPR)-based fiber-optic probes is dependent on surface coverage of gold nanoparticles (GNP), fiber core diameter, and probe geometry. For U-bent LSPR fiber-optic probes, which demonstrated an order higher absorption sensitivity over straight probes, bend diameter and probe length may also have a significant influence on the sensitivity. This study on U-bent fiber-optic LSPR probes is aimed at optimizing these parameters to obtain highest possible RI sensitivity. RI sensitivity increases linearly as a function of surface coverage of GNP in the range of 2-22 %. U-bent fiber-optic probes made of 200-, 400-, and 600-mu m fiber core diameter show optimum bend diameter value as -1.4 mm. In addition, RI sensitivity is almost the same irrespective of fiber core diameter demonstrating flexibility in choice of the fiber and ease in optical coupling. The length of the probe preceding and succeeding the bend region has significantly less influence on RI sensitivity allowing miniaturization of these probes. In addition to these experimental studies, we present a theoretical analysis to understand the relative contribution of evanescent wave absorbance of GNP and refractive losses in the fiber due to GNP, towards the RI sensitivity.