The MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand.
J Phys Chem A. 2012 Jan 26;116(3):1000-7. doi: 10.1021/jp2107507. Epub 2012 Jan 17.
A novel hybrid spectroscopic technique is proposed, combining surface plasmon resonance (SPR) with surface-enhanced Raman scattering (SERS) microscopy. A standard Raman microscope is modified to accommodate the excitation of surface plasmon-polaritons (SPPs) on flat metallic surfaces in the Kretschmann configuration, while retaining the capabilities of Raman microscopy. The excitation of SPPs is performed as in standard SPR-microscopy; namely, a beam with TM-polarization traverses off-axis a high numerical aperture oil immersion objective, illuminating at an angle the metallic film from the (glass) substrate side. The same objective is used to collect the full Kretschmann cone containing the SERS emission on the substrate side. The angular dispersion of the plasmon resonance is measured in reflectivity for different coupling conditions and, simultaneously, SERS spectra are recorded from Nile Blue (NB) molecules adsorbed onto the surface. A trade-off is identified between the conditions of optimum coupling to SPPs and the spot size (which is related to the spatial resolution). This technique opens new horizons for SERS microscopy with uniform enhancement on flat surfaces.
提出了一种新颖的混合光谱技术，将表面等离子体共振（SPR）与表面增强拉曼散射（SERS）显微镜相结合。标准拉曼显微镜经过修改，可在克来斯琴配置中在平面金属表面上激发表面等离子体激元（SPP），同时保留拉曼显微镜的功能。SPP 的激发与标准 SPR 显微镜相同；即，具有 TM 偏振的光束从离轴穿过高数值孔径油浸物镜，从（玻璃）基底侧以一定角度照射金属膜。同一物镜用于收集基底侧上包含 SERS 发射的全克来斯琴锥。对于不同的耦合条件，在反射率中测量等离子体共振的角色散，同时从吸附在表面上的尼罗蓝（NB）分子记录 SERS 光谱。在 SPP 最佳耦合条件和光斑尺寸（与空间分辨率有关）之间确定了一种权衡关系。该技术为具有平面表面均匀增强的 SERS 显微镜开辟了新的前景。
