TY - JOUR
T1 - Robust plasmonic hot-spots in a metamaterial lattice for enhanced sensitivity of infrared molecular detection
AU - Ishikawa, Atsushi
AU - Hara, Shuhei
AU - Tanaka, Takuo
AU - Zhang, Xiang
AU - Tsuruta, Kenji
N1 - Funding Information:
This work was supported in part by the JSPS KAKENHI Grant No. 15KK0237, the Gordon and Betty Moore Foundation, and the Office of Naval Research (ONR) MURI program Grant No. N00014-13-1-0649. The nanofabrication in this work was performed at the Division of Instrumental Analysis, Okayama University.
Publisher Copyright:
© 2017 Author(s).
PY - 2017/12/11
Y1 - 2017/12/11
N2 - High-density and long-lived plasmonic hot-spots are an ideal system for high-sensitive surface-enhanced infrared absorption (SEIRA), but these conditions are usually incompatible due to unwanted near-field coupling between the adjacent unit structures. Here, by fully controlling plasmonic interference in a metamaterial lattice, we experimentally demonstrate densely packed long-lived quadrupole plasmons for high-sensitive SEIRA. The metamaterial consists of a strongly coupled array of super- and sub-radiant plasmonic elements to exhibit an electromagnetic transparency mode at 1730 cm-1, which spectrally overlaps with the C=O vibrational mode. In the SEIRA measurement, the C=O mode of poly(methyl methacrylate) molecules is clearly observed as a distinct dip within a transmission peak of the metamaterial. The corresponding numerical simulations reveal that constructive interference uniformly forms coherent quadrupole plasmons over the metamaterial lattice, leading to a stronger molecular signal from the system. Our metamaterial approach provides a robust way to construct ideal hot-spots over the sample, paving the way toward a reliable sensing platform of advanced infrared inspection technologies.
AB - High-density and long-lived plasmonic hot-spots are an ideal system for high-sensitive surface-enhanced infrared absorption (SEIRA), but these conditions are usually incompatible due to unwanted near-field coupling between the adjacent unit structures. Here, by fully controlling plasmonic interference in a metamaterial lattice, we experimentally demonstrate densely packed long-lived quadrupole plasmons for high-sensitive SEIRA. The metamaterial consists of a strongly coupled array of super- and sub-radiant plasmonic elements to exhibit an electromagnetic transparency mode at 1730 cm-1, which spectrally overlaps with the C=O vibrational mode. In the SEIRA measurement, the C=O mode of poly(methyl methacrylate) molecules is clearly observed as a distinct dip within a transmission peak of the metamaterial. The corresponding numerical simulations reveal that constructive interference uniformly forms coherent quadrupole plasmons over the metamaterial lattice, leading to a stronger molecular signal from the system. Our metamaterial approach provides a robust way to construct ideal hot-spots over the sample, paving the way toward a reliable sensing platform of advanced infrared inspection technologies.
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U2 - 10.1063/1.5004703
DO - 10.1063/1.5004703
M3 - Article
AN - SCOPUS:85038440827
SN - 0003-6951
VL - 111
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 24
M1 - 243106
ER -