Nanophotonics Research Center, Shenzhen Key Laboratory of Micro-Scale Optical Information Technology, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China.
Sensors (Basel). 2020 Nov 23;20(22):6687. doi: 10.3390/s20226687.
A tip-enhanced Raman spectroscopy (TERS) system based on an atomic force microscope (AFM) and radially polarized laser beam was developed. A TERS probe with plasmon resonance wavelength matching the excitation wavelength was prepared with the help of dark-field micrographs. The intrinsic photoluminescence (PL) from the silver (Ag)-coated TERS probe induced by localized surface plasmon resonance contains information about the near-field enhanced electromagnetic field intensity of the probe. Therefore, we used the intensity change of Ag PL to evaluate the stability of the Ag-coated probe during TERS experiments. Tracking the Ag PL of the TERS probe was helpful to detect probe damage and hotspot alignment. Our setup was successfully used for the TERS imaging of single-walled carbon nanotubes, which demonstrated that the Ag PL of the TERS probe is a good criterion to assist in the hotspot alignment procedure required for TERS experiments. This method lowers the risk of contamination and damage of the precious TERS probe, making it worthwhile for wide adoption in TERS experiments.
我们开发了一种基于原子力显微镜（AFM）和径向偏振激光束的尖端增强拉曼光谱（TERS）系统。借助暗场显微镜制备了具有等离子体共振波长与激发波长匹配的TERS 探针。由局域表面等离子体共振诱导的银（Ag）覆盖 TERS 探针的固有光致发光（PL）包含有关探针近场增强电磁场强度的信息。因此，我们使用 Ag PL 的强度变化来评估 TERS 实验过程中 Ag 涂层探针的稳定性。跟踪 TERS 探针的 Ag PL 有助于检测探针的损坏和热点对准。我们的设置成功地用于单壁碳纳米管的 TERS 成像，这表明 TERS 探针的 Ag PL 是辅助 TERS 实验所需的热点对准过程的一个很好的标准。这种方法降低了珍贵的 TERS 探针污染和损坏的风险，使其在 TERS 实验中值得广泛采用。
