Beketov Gennadii V, Shynkarenko Olena V, Yukhymchuk Volodymyr O
V. Lashkaryov Institute of Semiconductor Physics of National Academy of Sciences (NAS) of Ukraine, 41 pr. Nauky, 03028 Kyiv, Ukraine.
V. Lashkaryov Institute of Semiconductor Physics of National Academy of Sciences (NAS) of Ukraine, 41 pr. Nauky, 03028 Kyiv, Ukraine.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Aug 5;219:488-495. doi: 10.1016/j.saa.2019.04.039. Epub 2019 Apr 23.
We present an optical arrangement for spectroscopy of enhanced Raman scattering assisted by surface plasmon resonance in continuous planar metallic films. Optical excitation of propagating surface plasmons (PSP) is aided by the hemispherical total internal reflectance prism in the Kretschmann geometry. In this geometry, the radiation produced by Raman scattering is directionally emitted inside the prism with the angular distribution in the shape of a hollow cone (the Kretschmann cone). The proposed configuration enables entire collection of the Kretschmann cone with the use of an elliptical mirror modified for enlarging the accessible angular range for both the incident beam and the scattered light. The spectroscopic performance of this arrangement was evaluated using the Rhodamine 6G dye as a surface enhanced Raman scattering (SERS) reporter. An evident difference in magnitudes of the enhancement factor for specific spectral lines as compared to SERS excitation by localized surface plasmon resonance (LSPR-SERS) was revealed. The origin of this difference is discussed in terms of expected distinctions between the PSP-assisted directional enhanced Raman scattering and the LSPR-SERS. Besides the spectroscopic applications, the proposed arrangement is also perfectly suited for simultaneous functioning as the SPR sensor. Integration of SERS spectroscopy with the SPR analysis shows promise as a platform for evolving an innovative analytical technique with enhanced potentialities in surface research, particularly in biochemical applications.
我们展示了一种用于连续平面金属膜中表面等离子体共振辅助增强拉曼散射光谱的光学装置。在Kretschmann几何结构中，半球形全内反射棱镜有助于传播表面等离子体（PSP）的光激发。在这种几何结构中，拉曼散射产生的辐射在棱镜内部定向发射，其角分布呈空心圆锥形状（Kretschmann圆锥）。所提出的配置能够通过使用经过修改的椭圆镜来收集整个Kretschmann圆锥，该椭圆镜用于扩大入射光束和散射光的可及角范围。使用罗丹明6G染料作为表面增强拉曼散射（SERS）报告分子评估了这种装置的光谱性能。与通过局域表面等离子体共振（LSPR-SERS）进行的SERS激发相比，特定光谱线的增强因子大小存在明显差异。从PSP辅助的定向增强拉曼散射与LSPR-SERS之间的预期差异方面讨论了这种差异的起源。除了光谱应用外，所提出的装置还非常适合同时用作SPR传感器。将SERS光谱与SPR分析相结合，有望成为一个平台，用于发展一种在表面研究中具有增强潜力的创新分析技术，特别是在生化应用中。
