Previous studies of the gold-nanoparticles-covered U-type medical optical fiber sensor with millimeter size were mainly confined to the experimental aspect, while the corresponding theoretical studies were only for bare fibers based on geometrical optics or those for micron level photonic crystal fibers based on wave optics. Combining wave and geometrical optics, the gold-nanoparticles-covered U-type optical fiber sensor was simulated with millimeter size. The localized surface plasmon resonance absorption peak near 540 nm is obtained in the simulation, very close to that (≈560 nm) of the experimental value for the gold nanoparticles of 37 nm size. Compared with the refractive index (RI) sensitivity (≈7.10/RIU) for the plain, U-type optical fiber (≈43.50/RIU) exhibits more than 610% enhancement in the gold-nanoparticles-covered sample. Present studies would be helpful to the further simulation and design for various noble metal nanoparticles covered optical fiber sensors with different shapes.

中文翻译：

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金纳米粒子覆盖的医用U型光纤传感器的理论研究

先前对金纳米粒子覆盖的U型医用光纤传感器的研究主要限于实验方面，而相应的理论研究仅针对基于几何光学的裸纤维或基于微米级的光子晶体光纤的理论研究。在波光学上。将波和几何光学相结合，用毫米尺寸模拟了覆盖金纳米粒子的U型光纤传感器。在模拟中获得了接近540 nm的局部表面等离子体共振吸收峰，非常接近于37 nm尺寸的金纳米颗粒的实验值（≈560nm）。与普通的折射率（RI）灵敏度（≈7.10/ RIU）相比，U型光纤（≈43.50/ RIU）在覆盖金纳米颗粒的样品中表现出超过610％的增强。