1 research outputs found
Subradiant Dipolar Interactions in Plasmonic Nanoring Resonator Array for Integrated Label-Free Biosensing
With
the development of advanced nanofabrication technologies over
the past decade, plasmonic nanostructures have attracted wide attention
for their potential in label-free biosensing applications. However,
the sensing performance of nanostructured plasmonic sensors is primarily
limited by the broad-line-width features with low peak-to-dip signal
ratio in the extinction spectra that result from strong radiative
damping. Here, we propose and systematically investigate the in-plane
and out-of-plane dipolar interactions in an array of plasmonic nanoring
resonators that are from the spatial combination of classic nanohole
and nanodisk structures. Originating from the strong coupling of the
dipolar modes from parent nanohole and nanodisk structures, the subradiant
lattice plasmon resonance in the nanoring resonator array exhibits
narrow-line width spectral features with high peak-to-dip signal ratio
and strong near-field electromagnetic enhancement, making it an ideal
platform for high-sensitivity chemical and biomedical sensing. We
experimentally demonstrate that the plasmonic nanoring resonator array
can be used for high-sensitivity refractive index sensing and real-time
monitoring of biomolecular specific binding interactions at nanomolar
concentration. Moreover, due to its simple normal incident illumination
scheme and polarization independent optical response, we further transfer
the plasmonic nanoring resonator array onto the optical fiber tip
to demonstrate an integrated and miniaturized platform for label-free
remote biosensing, which implies that the plasmonic nanoring resonator
array may be a potential candidate for developing high performance
and highly integrated photonic biosensing systems