Kim Taehyun, Lee Jongsu, Yu Eui-Sang, Lee Seungha, Woo Hyeonbin, Kwak Jeonghun, Chung Seok, Choi Inhee, Ryu Yong-Sang
Center for Brain Technology, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea.
Department of Micro/Nano Systems, Korea University, Seoul, 02841, Republic of Korea.
Small. 2023 Jul;19(29):e2207003. doi: 10.1002/smll.202207003. Epub 2023 Apr 5.
The Fabry-Perot (FP) resonator is an intuitive and versatile optical structure owing to its uniqueness in light-matter interactions, yielding resonance with a wide range of wavelengths as it couples with photonic materials encapsulated in a dielectric cavity. Leveraging the FP resonator for molecular detection, a simple geometry of the metal-dielectric-metal structure is demonstrated to allow tuning of the enhancement factors (EFs) of surface-enhanced Raman scattering (SERS). The optimum near-field EF from randomly dispersed gold nano-gaps and dynamic modulation of the far-field SERS EF by varying the optical resonance of the FP etalon are systematically investigated by performing computational and experimental analyses. The proposed strategy of combining plasmonic nanostructures with FP etalons clearly reveals wavelength matching of FP resonance to excitation and scattering wavelengths plays a key role in determining the magnitude of the SERS EF. Finally, the optimum near-field generating optical structure with controlled dielectric cavity is suggested for a tunable SERS platform, and its dynamic SERS switching performance is confirmed by demonstrating information encryption through liquid immersion.
法布里-珀罗（FP）谐振器是一种直观且通用的光学结构，因其在光与物质相互作用方面的独特性，在与封装在介电腔中的光子材料耦合时能产生宽波长范围的共振。利用FP谐振器进行分子检测，展示了一种简单的金属-电介质-金属结构几何形状，可实现表面增强拉曼散射（SERS）增强因子（EFs）的调谐。通过进行计算和实验分析，系统地研究了随机分散的金纳米间隙的最佳近场EF以及通过改变FP标准具的光学共振对远场SERS EF的动态调制。将等离子体纳米结构与FP标准具相结合的所提出策略清楚地表明，FP共振与激发和散射波长的波长匹配在确定SERS EF的大小中起关键作用。最后，针对可调谐SERS平台提出了具有可控介电腔的最佳近场产生光学结构，并通过液体浸没演示信息加密来证实其动态SERS切换性能。
