Tip-enhanced Raman scattering of glucose molecules
Zhonglin Xie, Chao Meng, D Yue, Lei Xu, Ting Mei, Wending Zhang
Abstract
Glucose molecules are of great significance being one of the most important molecules in metabolic chain. However, due to the small Raman scattering cross-section and weak/non-adsorption on bare metals, accurately obtaining their "fingerprint information" remains a huge obstacle. Herein, we developed a tip-enhanced Raman scattering (TERS) technique to address this challenge. Adopting an optical fiber radial vector mode internally illuminates the plasmonic fiber tip to effectively suppress the background noise while generating a strong electric-field enhanced tip hotspot. Furthermore, the tip hotspot approaching the glucose molecules was manipulated via the shear-force feedback to provide more freedom for selecting substrates. Consequently, our TERS technique achieves the visualization of all Raman modes of glucose molecules within spectral window of 400–<styled-content style-type="number">3200</styled-content> cm<sup>−1</sup>, which is not achievable through the far-field/surface-enhanced Raman, or the existing TERS techniques. Our TERS technique offers a powerful tool for accurately identifying Raman scattering of molecules, paving the way for biomolecular analysis.