Damle Vinayaka H, Sinwani Miri, Aviv Hagit, Tischler Yaakov R
Department of Chemistry, Institute for Nanotechnology and Advanced Materials (BINA) Bar-Ilan University, Ramat Gan 52900002, Israel.
Sensors (Basel). 2020 Mar 7;20(5):1470. doi: 10.3390/s20051470.
Raman spectroscopy is a widely used characterization technique in material science. It is a non-destructive tool with relatively simple instrumentation, and provides intrinsic qualitative information of analytes by probing their vibrational modes. In many cases, Raman enhancement is essential for detecting low-intensity signals in high-noise environments, spectrally unresolved features, and hidden modes. Here we present optical and Raman spectroscopic characterization of fullerene C 60 in a gold microcavity. The fabrication of single-layered gold mirrors is facile, low cost and direct but was proven to give considerably significant enhancement. The findings of this work demonstrate the cavity resonance as a powerful tool in obtaining tunability over individual peak for selective enhancement in the tuned spectral range. The PL of the material within the cavity has demonstrated a red shift assumed to be caused by the low-energy transitions. These transitions are induced by virtual low-energy states generated by the cavity. We further observe that adopting this principle enables resolution of active Raman modes that until now were unobserved. Finally, we assigned the new experimentally observed modes to the corresponding motions calculated by DFT.
拉曼光谱是材料科学中广泛使用的表征技术。它是一种具有相对简单仪器的非破坏性工具，通过探测分析物的振动模式提供其内在的定性信息。在许多情况下，拉曼增强对于在高噪声环境中检测低强度信号、光谱未解析特征和隐藏模式至关重要。在此，我们展示了金微腔中富勒烯C60的光学和拉曼光谱表征。单层金镜的制造简便、成本低且直接，但已被证明能产生相当显著的增强效果。这项工作的发现表明，腔共振是在调谐光谱范围内获得单个峰的可调性以实现选择性增强的有力工具。腔内材料的光致发光已显示出红移，推测是由低能跃迁引起的。这些跃迁是由腔产生的虚拟低能态诱导的。我们进一步观察到，采用这一原理能够分辨出迄今为止未被观察到的活性拉曼模式。最后，我们将新的实验观察到的模式与通过密度泛函理论（DFT）计算的相应运动进行了关联。
