Far-field nanoscale infrared spectroscopy of vibrational fingerprints of molecules with graphene plasmons

Hai Hu, Xiaoxia Yang, Feng Zhai, Debo Hu, Ruina Liu, Kaihui Liu, Zhipei Sun, Qing Dai*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

149 Citations (Scopus)
162 Downloads (Pure)

Abstract

Infrared spectroscopy, especially for molecular vibrations in the fingerprint region between 600 and 1,500 cm -1, is a powerful characterization method for bulk materials. However, molecular fingerprinting at the nanoscale level still remains a significant challenge, due to weak light-matter interaction between micron-wavelengthed infrared light and nano-sized molecules. Here we demonstrate molecular fingerprinting at the nanoscale level using our specially designed graphene plasmonic structure on CaF 2 nanofilm. This structure not only avoids the plasmon-phonon hybridization, but also provides in situ electrically-tunable graphene plasmon covering the entire molecular fingerprint region, which was previously unattainable. In addition, undisturbed and highly confined graphene plasmon offers simultaneous detection of in-plane and out-of-plane vibrational modes with ultrahigh detection sensitivity down to the sub-monolayer level, significantly pushing the current detection limit of far-field mid-infrared spectroscopies. Our results provide a platform, fulfilling the long-awaited expectation of high sensitivity and selectivity far-field fingerprint detection of nano-scale molecules for numerous applications.

Original languageEnglish
Article number12334
Pages (from-to)1-8
Number of pages8
JournalNature Communications
Volume7
DOIs
Publication statusPublished - 27 Jul 2016
MoE publication typeA1 Journal article-refereed

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