Photochemically synthesized silver nanostructures on tapered fiber as plasmonic tweezers for surface enhanced Raman scattering applications

• Photochemically synthesized silver nanostructures are fabricated on a tapered fiber.
• The synthesis of the nanostructures is assisted by evanescent light from the fiber taper.
• Trapping and releasing of target molecules is experimentally verified by monitoring surface enhanced Raman scattering (SERS).
• The maximum SERS signal enhancement factor is ∼106.

A photochemically synthesized silver nanostructure has been fabricated on a tapered fiber. The possibility of using it for controlled trapping and releasing of target silver nanoparticles is experimentally verified. The evanescent light from fiber taper assists the synthesis of its nanostructures. After the same light source is coupled into the fiber again, the as-prepared silver nanostructure-coated tapered fiber (AgNS-TF) acts as plasmonic tweezers for trapping silver nanodecahedrons (AgNDs) with target Raman molecules immobilized on. Then we confirm the trapping event by monitoring surface enhanced Raman scattering (SERS) signals at the AgNS-TF. The proposed fiber-based scheme offers a flexible device platform for low-cost portable sensing applications.