ph500126v_si_001.pdf (966.22 kB)
Download fileMiniaturized Sensing Probes Based on Metallic Dielectric Crystals Self-Assembled on Optical Fiber Tips
journal contribution
posted on 2014-10-15, 00:00 authored by Marco Pisco, Francesco Galeotti, Giuseppe Quero, Agostino Iadicicco, Michele Giordano, Andrea CusanoWe
propose a novel fabrication process to realize optical sensing
probes based on metal–dielectric crystals self-assembled on
an optical fiber tip. The breath figure methodology has been adapted
to work directly on nonconventional substrates, such as optical fibers,
enabling the formation of regular and ordered metallo-dielectric crystals
on optical fiber tips. Accurate morphological characterization was
carried out to qualify the fabrication process. The reported results
indicate that the proposed fabrication technique provides a method
for rapid and cost-effective prototyping of photonic–plasmonic
nanoprobes for sensing applications. To achieve this goal, we develop
a technological platform via the addition of polymer–metal
crystals onto the tip of a standard single optical fiber, which is
able to support surface plasmon resonances in the near-infrared. A
dedicated numerical tool was developed to study and analyze arbitrary
subwavelength structures integrated on the optical fiber tip by taking
into account finite-size effects. The numerical results are in good
agreement with the observed experimental spectra and reveal that the
fabricated sensing probes act as structured interferometers that are
assisted by surface plasmon excitations at the metallo-dielectric
interfaces. To prove the sensing capability of the proposed platform,
refractive index measurements were carried out, revealing a sensitivity
of up to 2300 nm/RIU, outperforming most plasmonic probes synthesized
on optical fiber tips. The achieved performances, obtained using very
small active areas, demonstrate the effectiveness of these self-assembled
fiber-optic probes for label-free chemical and biological sensing
applications.