采用化学腐蚀法制备锥形光纤,采用溶液化学沉积法将银纳米颗粒修饰到锥形光纤端面,形成光纤表面增强拉曼散射(SERS)探针。改变反应温度、沉积时间、硝酸银溶液浓度等关键参数,优化了光纤SERS探针的制备工艺。以R6G为探针分子,对不同工艺条件制备的光纤SERS探针进行拉曼测试实验。结果表明:在室温下,当沉积时间为120 s、硝酸银溶液浓度为0.1 mol/L时,最优的增强因子约为10 ¹⁰,此时光纤SERS探针的拉曼检测性能最好。对应10组样品的银纳米颗粒的直径和面积覆盖率,利用FDTD Solutions进行仿真建模分析,计算得到了拉曼增强因子理论值为10 ⁷~10 ⁸。

A tapered fiber is prepared with a simple chemical etching method, and modified with Ag nanoparticles (AgNPs) by solution chemical deposition method to prepare the tapered fiber surface-enhanced Raman scattering (SERS) probe. The preparation process is optimized by the change of key parameters, such as reaction temperature, deposition time and the concentration of silver nitrate solution. The Raman measurement experiments of the fiber SERS probes under different preparation process conditions are completed. The results indicate that the best Raman measurement performance of the tapered fiber SERS probe can be acquired at room temperature, when the deposition time is 120 s, the concentration of silver nitrate solution is 0.1 mol/L, and the optimal enhancement factor is about 10 10. In addition, corresponding to ten samples with different sizes of AgNPs and the coverage areas, we adopt FDTD Solutions to calculate the enhancement factor and obtain theoretical Raman enhancement factor of 10 7-10 8.