Boron nitride nanoresonators for phonon-enhanced molecular vibrational spectroscopy at the strong coupling limit
Boron nitride nanoresonators for phonon-enhanced molecular vibrational spectroscopy at the strong coupling limit
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DOI：
10.1038/lsa.2017.172
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发表时间：
2018-04-06
影响因子：
19.4
通讯作者：
Hillenbrand, Rainer
中科院分区：
文献类型：
--
作者：
Autore, Marta;Li, Peining;Hillenbrand, Rainer
增强的光与物质相互作用是表面增强红外吸收（SEIRA）光谱的基础，通常依赖于等离子体材料及其将光聚焦到纳米级光斑尺寸的能力。由极性晶体制成的声子极化子纳米谐振器可能是一种有趣的替代方案，因为它们表现出很大的品质因数，远远超出了等离激元对应物。最近出现的范德华晶体使得能够制造基于声子极化子的高质量纳米光子谐振器，正如典型红外声子材料六方氮化硼（h-BN）所报道的那样。在这项工作中，我们首次使用声子极化子共振 h-BN 带进行傅里叶变换红外光谱中少量有机分子的 SEIRA 光谱分析。引人注目的是，声子极化子和分子振动之间的相互作用在实验上达到了强耦合状态的开始，而数值模拟预测振动强耦合可以完全实现。因此，声子极化子纳米谐振器可以成为传感、化学反应性局部控制和红外量子腔光学实验的可行平台。
Enhanced light-matter interactions are the basis of surface-enhanced infrared absorption (SEIRA) spectroscopy, and conventionally rely on plasmonic materials and their capability to focus light to nanoscale spot sizes. Phonon polariton nanoresonators made of polar crystals could represent an interesting alternative, since they exhibit large quality factors, which go far beyond those of their plasmonic counterparts. The recent emergence of van der Waals crystals enables the fabrication of high-quality nanophotonic resonators based on phonon polaritons, as reported for the prototypical infrared-phononic material hexagonal boron nitride (h-BN). In this work we use, for the first time, phonon-polariton-resonant h-BN ribbons for SEIRA spectroscopy of small amounts of organic molecules in Fourier transform infrared spectroscopy. Strikingly, the interaction between phonon polaritons and molecular vibrations reaches experimentally the onset of the strong coupling regime, while numerical simulations predict that vibrational strong coupling can be fully achieved. Phonon polariton nanoresonators thus could become a viable platform for sensing, local control of chemical reactivity and infrared quantum cavity optics experiments.