Functionalization of metallic surfaces by molecular monolayers is a key process in fields such as nanophotonics or biotechnology. To strongly enhance light–matter interaction in such monolayers, nanoparticle-on-a-mirror (NPoM) cavities can be formed by placing metal nanoparticles on such chemically functionalized metallic monolayers. In this work, we present a novel functionalization process of gold surfaces using 5-amino-2-mercaptobenzimidazole (5-A-2MBI) molecules, which can be used for upconversion from THz to visible frequencies. The synthesized surfaces and NPoM cavities are characterized by Raman spectroscopy, atomic force microscopy (AFM), and advancing–receding contact angle measurements. Moreover, we show that NPoM cavities can be efficiently integrated on a silicon-based photonic chip performing pump injection and Raman-signal extraction via silicon nitride waveguides. Our results open the way for the use of 5-A-2MBI monolayers in different applications, showing that NPoM cavities can be effectively integrated with photonic waveguides, enabling on-chip enhanced Raman spectroscopy or detection of infrared and THz radiation.

中文翻译：

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介电波导驱动的镜上纳米颗粒等离子体腔中 5-氨基-2-巯基苯并咪唑自组装单层的合成和拉曼检测

通过单分子层对金属表面进行功能化是纳米光子学或生物技术等领域的关键过程。为了强烈增强此类单层中的光与物质相互作用，可以通过将金属纳米颗粒放置在此类化学功能化的金属单层上来形成镜上纳米颗粒（NPoM）空腔。在这项工作中，我们提出了一种使用 5-氨基-2-巯基苯并咪唑 (5-A-2MBI) 分子对金表面进行新型功能化的方法，该方法可用于从太赫兹频率到可见频率的上转换。合成表面和 NPoM 腔体通过拉曼光谱、原子力显微镜 (AFM) 和前进-后退接触角测量进行表征。此外，我们还表明，NPoM 腔可以有效地集成在硅基光子芯片上，通过氮化硅波导执行泵浦注入和拉曼信号提取。我们的研究结果为 5-A-2MBI 单层在不同应用中的使用开辟了道路，表明 NPoM 腔可以有效地与光子波导集成，从而实现片上增强拉曼光谱或红外和太赫兹辐射的检测。