Refractive index sensing using disk-hole coupling plasmonic structures fabricated on fiber facet

We report a cost-effective and high-throughput method, featuring a double-transfer process and through-fiber curing, to pattern metallic nanostructures on optical fiber facet as portable plasmonic probes for refractive index (RI) sensing. A thin layer of ultraviolet-curable adhesive is coated onto fiber facet to imprint-transfer pre-fabricated metallic nanostructures from a polymeric template to the fiber facet. The reflection spectra of the plasmonic fiber probe in liquid solution samples with various RI are experimentally investigated to demonstrate its capability for real-time and in situ RI sensing. The optical reflection and local electric field distribution of the plasmonic sensing structures are also investigated through numerical modeling. The fiber-facet plasmonic sensor exhibits robust and flexible potential for RI-based sensing applications, and the reported fabrication method is applicable for the production of other functional nanodevices on fiber facets.