jp5b04791_si_001.pdf (1.22 MB)
Leaky Mode Resonance of Polyimide Waveguide Couples Metal Plasmon Resonance for Surface-Enhanced Raman Scattering
journal contribution
posted on 2015-11-05, 00:00 authored by Shuai Wang, Zhiyong Wu, Lei Chen, Yuejiao Gu, Hailong Wang, Shuping Xu, Weiqing XuIn
the studies of surface-enhanced Raman scattering (SERS), it
is considered to be a key point to couple the surface plasmons of
metallic nanomaterials and structures to resonate, which can assist
higher SERS signal enhancement. This paper is to explore a strategy
for plasmon resonating based on the leaky mode resonance (LMR) of
a polyimide (PI) optical waveguide (OWG), for the purpose of achieving
the highly sensitive evanescent field-excited SERS. PI was chosen
to build the waveguide layer due to its merits of exhibiting small
extinction coefficients in the natural light frequency, low cost,
high flexibility, easy fabrication, and almost no Raman spectral interference.
The OWG configuration guarantees a high harvesting efficiency for
the incident light. Ag nanoparticles were assembled on top of the
OWG layer as plasmonic antennas to provide a large scattering cross
section based on the coupling of the LMR and metal plasmon resonance
(MPR), which supports highly efficient SERS radiation and being conducive
to the far-field collection. The LMR-MPR coupling can facilitate stronger
local electromagnetic field around the side surfaces of the Ag nanoparticles,
which is favorable to the adsorption of analytes. The PI OWG-coupled
MPR structure can realize the integration of SERS excitation light
paths and elements, which is not only a valuable SERS enhancement
configuration but also a promising technique for the surface and thin
film analysis.