In this research, we propose a novel microlens surface-enhanced Raman spectroscopy (SERS) substrate @ Au film detection system, which is shown to have excellent attributes. This scheme involves the construction of a PDMS plano-convex microlens SERS-active substrate in combination with an Au film. Due to the optical convergence from the microlens, the synergistic enhancement effects due to the Au film, and the “Au film–molecules–AgNPs” sandwich structure, an outstanding SERS performance is achieved. Multiple tests using a portable Raman spectrometer show that the optical convergence due to the microlens and the coupling effects contribute around 1.85× and 26.18× enhancement of the Raman signal, respectively. Even for objective lenses with different numerical apertures, simulations show that the microlens SERS substrate can further enhance the signal collection efficiency; this indicates that the detection scheme is universally applicable. Moreover, the microlens SERS substrate @ Au film system shows excellent time stability, and its Raman enhancement performance remains consistently above 98% of the original signal, even one week later. Our proposed system is simple to prepare, is low cost and has many potential practical applications, which include the detection of biochemical samples.

中文翻译：

---

基于光会聚和协同增强效应的夹心SERS检测系统

在这项研究中，我们提出了一种新型的微透镜表面增强拉曼光谱 (SERS) 衬底@Au 膜检测系统，该系统被证明具有优异的属性。该方案涉及与 Au 膜相结合的 PDMS 平凸微透镜 SERS 活性基板的构造。由于微透镜的光学会聚、Au 膜的协同增强效果以及“Au 膜-分子-AgNPs”夹层结构，实现了出色的 SERS 性能。使用便携式拉曼光谱仪的多项测试表明，由于微透镜和耦合效应引起的光学会聚分别对拉曼信号的增强贡献了大约 1.85 倍和 26.18 倍。即使对于数值孔径不同的物镜，仿真表明，微透镜SERS基板可以进一步提高信号采集效率；这表明检测方案是普遍适用的。此外，微透镜SERS基板@Au薄膜系统显示出优异的时间稳定性，其拉曼增强性能即使在一周后仍能始终保持在原始信号的98%以上。我们提出的系统制备简单，成本低，具有许多潜在的实际应用，包括生化样品的检测。