Subwavelength Terahertz Resonance Imaging (STRING) for Molecular Fingerprinting

Taewoo Ha, Daehan Yoo, Chaejeong Heo, Ferran Vidal-Codina, Ngoc Cuong Nguyen, Kyung Ik Sim, Sang Hyun Park, Wujoon Cha, Sungsu Park, Jaime Peraire, Teun Teun Kim, Young Hee Lee, Sang Hyun Oh

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Subwavelength terahertz (THz) imaging methods are highly desirable for biochemical sensing as well as materials sciences, yet sensitive spectral fingerprinting is still challenging in the frequency domain due to weak light-matter interactions. Here, we demonstrate subwavelength THz resonance imaging (STRING) that overcomes this limitation to achieve ultrasensitive molecular fingerprinting. STRING combines individual ring-shaped coaxial single resonators with near-field spectroscopy, yielding considerable sensitivity gains from both local field enhancement and the near-field effect. As an initial demonstration, we obtained spectral fingerprints from isomers of α-lactose and maltose monohydrates, achieving sensitivity that was enhanced by up to 10 orders of magnitude compared to far-field THz measurements with pelletized samples. Our results show that the STRING platform could enable the development of THz spectroscopy as a practical and sensitive tool for the fingerprinting and spectral imaging of molecules and nanoparticles.

Original languageEnglish (US)
Pages (from-to)10200-10207
Number of pages8
JournalNano letters
Issue number24
StatePublished - Dec 28 2022

Bibliographical note

Funding Information:
This research was supported by grants from the Institute for Basic Science (IBS-R011-D1 to T.H., C.H., K.I.S., S.H.P., W.C., Y.H.L., and T.-T.K.), the National Research Council of Science and Technology (CRC22021-200 to S.P.), the Samsung Global Research Outreach (GRO) Program and Sanford P. Bordeau Chair (to D.Y. and S.-H.O.), the U.S. AFOSR (FA9550-19-1-0240 to F.V.-C., N.-C.N., and J.P.), and the National Research Foundation of Korea (NRF-2021R1C1C1000631612 to T.-T.K.).

Publisher Copyright:
© 2022 American Chemical Society.


  • coaxial aperture
  • epsilon-near-zero (ENZ)
  • nanophotonics
  • near-field spectroscopy
  • spectral fingerprinting
  • terahertz imaging


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