Authors:	A. Raza, S. Clemmen, P.C. Wuytens, M. Muneeb, M. V. Daele, J. Dendooven, C. Detavernier, A. Skirtach, R. Baets
Title:	ALD assisted nanoplasmonic slot waveguide for on-chip Enhanced Raman Spectroscopy
Format:	International Journal
Publication date:	10/2018
Journal/Conference/Book:	Applied Physics Letters - Photonics
Editor/Publisher:	AIP,
Volume(Issue):	3(11) p.116105 (12 pages)
DOI:	10.1063/1.5048266
Citations:	35 (Dimensions.ai - last update: 21/4/2024) 11 (OpenCitations - last update: 19/4/2024) Look up on Google Scholar
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Abstract

Surface enhanced Raman spectroscopy (SERS) is a widely known sensing technique
that uses a plasmonic enhancement to probe analytes in ultra-small volumes. Re-
cently the integration of plasmonic structures with photonic integrated waveguides
promised the full integration of a SERS spectroscopy system on a chip. Unfortu-
nately, the previously reported sensors provide modest overall SERS enhancement
resulting in a limited signal to noise ratio. Here, we report a photonic waveguide
interfaced SERS sensor that shows an order of magnitude higher pump to Stokes
conversion eciency and lower background than previous realizations. Moreover, the
plasmonic structure is fabricated without the use of e-beam lithography but rather
using a combination of atomic layer deposition (ALD) and deep UV photolithogra-
phy. We investigate numerically the performance of the sensor in term of Raman
conversion eciency for various design parameters. The experimental results are
presented via the acquisition of SERS spectra that show a conversion efficiency of
10􀀀9 for a monolayer of 4-nitrothiophenol. To explore the broadband characteristic
of our sensor in the therapeutic spectral window, two dierent pump wavelengths
i.e. 632 and 785 nm are used. To the best of our knowledge, this is the rst ever
broadband SERS demonstration of an on-chip Raman sensor. We further study the
reproducibility of our SERS sensor, reaching a relative standard deviation of the
acquired spectra (RSD) < 5 %.

Related Research Topics

• Raman spectroscopy on a siliconnitride waveguide platform
• Nanoplasmonic approach for Raman spectroscopy on siliconnitride waveguides

Related Projects

• ERC-AdG: InSpectra (Silicon-photonics-based laser spectroscopy platform: towards a paradigm shift in environmental monitoring and health care)