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Waveguide-Integrated Compact Plasmonic Resonators for On-Chip Mid-Infrared Laser Spectroscopy.

Authors :
Chen C
Mohr DA
Choi HK
Yoo D
Li M
Oh SH
Source :
Nano letters [Nano Lett] 2018 Dec 12; Vol. 18 (12), pp. 7601-7608. Date of Electronic Publication: 2018 Sep 20.
Publication Year :
2018

Abstract

The integration of nanoplasmonic devices with a silicon photonic platform affords a new approach for efficient light delivery by combining the high field enhancement of plasmonics and the ultralow propagation loss of dielectric waveguides. Such a hybrid integration obviates the need for a bulky free-space optics setup and can lead to fully integrated, on-chip optical sensing systems. Here, we demonstrate ultracompact plasmonic resonators directly patterned atop a silicon waveguide for mid-infrared spectroscopic chemical sensing. The footprint of the plasmonic nanorod resonators is as small as 2 μm <superscript>2</superscript> , yet they can couple with the mid-infrared waveguide mode efficiently. The plasmonic resonance is directly measured through the transmission spectrum of the waveguide with a coupling efficiency greater than 70% and a field intensity enhancement factor of over 3600 relative to the evanescent waveguide field intensity. Using this hybrid device and a tunable mid-infrared laser source, surface-enhanced infrared absorption spectroscopy of both a thin poly(methyl methacrylate) film and an octadecanethiol monolayer is successfully demonstrated.

Details

Language :
English
ISSN :
1530-6992
Volume :
18
Issue :
12
Database :
MEDLINE
Journal :
Nano letters
Publication Type :
Academic Journal
Accession number :
30216715
Full Text :
https://doi.org/10.1021/acs.nanolett.8b03156