Surface-enhanced ultrafast two-dimensional vibrational spectroscopy with engineered plasmonic nano-antennas
Surface-enhanced ultrafast two-dimensional vibrational spectroscopy with engineered plasmonic nano-antennas
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DOI：
10.1063/5.0013956
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发表时间：
2020-08-07
影响因子：
4.4
通讯作者：
Rubtsov, Igor, V
中科院分区：
文献类型：
--
作者：
Chuntonov, Lev;Rubtsov, Igor, V
开发提供强近场增强的贵金属纳米结构基底使线性和非线性红外（IR）光谱的应用能够研究微小的样品量，例如纳米厚膜和分子单层。用于在纳米结构表面处的分子的光谱询问的电场的大的近场增强导致光谱特征的增强。这种增强与方法的非线性阶数成比例，为三阶和五阶IR方法提供特别大的信号增益，达到10（6）和10（8）原始增强因子，不根据询问样品的量进行调整。在这个角度来看，我们概述了天线状纳米结构的纳米阵列的发展中红外测量的进展，并说明其在线性，特别是非线性二维红外方法的使用。我们讨论了光，等离子体天线和分子激发之间的相互作用机制的研究如何受益于非线性二维时间分辨方法，其中涉及高阶缩放的信号与激发场，高灵敏度的信号本地化，和相干的激发在一个宽的带宽。另一方面，我们展示了如何通过这些先进的光谱方法的分子结构和超快动力学的研究受益于表面增强等离子天线的信号。
Development of noble metal nanostructure substrates that provide strong near-field enhancements enables applications of linear and nonlinear infrared (IR) spectroscopies to study minute sample quantities, such as nanometer thick films and molecular monolayers. Large near-field enhancements of the electric fields used for spectroscopic interrogation of molecules at the nanostructure surface result in enhancement of the spectroscopic signatures. This enhancement scales with the nonlinear order of the method, providing particularly large signal gains for third- and fifth-order IR methods, reaching 10(6) and 10(8) raw enhancement factors, not adjusted to the amount of interrogated sample. In this perspective, we overview the advances in the development of nano-arrays of antenna-like nanostructures for mid-IR measurements and illustrate their use in linear and especially nonlinear two-dimensional IR approaches. We discuss how studies of the interaction mechanisms between light, plasmonic antennas, and molecular excitations benefit from the nonlinear two-dimensional time-resolved methods, which involve high-order scaling of the signal with the excitation field, high sensitivity to signal localization, and coherence of the excitation over a broad bandwidth. On the other hand, we demonstrate how studies of molecular structure and ultrafast dynamics by these advanced spectroscopic methods benefit from surface enhancement of signals by plasmonic antennas.