FDTD Simulation Research Based on SERS Analysis

表面增强拉曼散射(SERS)是一种强大的分析技术，可以增强拉曼散射产生的固有弱拉曼信号。以福美双为探针分子，采用三种不同生长时间的银纳米薄膜作为基底进行SERS检测。通过建立基底的物理模型，定义模拟区域，设置光源和监视器几个步骤搭建FDTD计算模型，并利用FDTD模拟来分析SERS增强机理。基于实验和仿真结果表明，当银纳米薄膜的生长时间为60 min时，展现出最佳的SERS活性。根据基底微观结构的FDTD模拟电场分布，可以发现纳米结构之间小于10 nm的超小纳米间隙可以激发大量的热点，从而放大拉曼信号。Surface-enhanced Raman scattering (SERS) is a powerful analytical technique that enhances inherently weak Raman signals generated by Raman scattering. Using thiram as a probe molecule, three kinds of silver nanofilms with different growth times were used as the substrate for SERS detection. The FDTD calculation model is constructed by establishing the physical model of the base, defining the simulation area, and setting up the light source and the monitor. FDTD simulation was used to analyze the SERS enhancement mechanism. Based on the experimental and simulation results, the best SERS activity was displayed when the growth time of silver nanofilms was 60 min. According to the FDTD simulation of the electric field distribution of the substrate microstructure, it can be found that the ultra-small nanogaps less than 10 nm between the nanostructures can excite a large number of hot spots, thus amplifying the Raman signal.