Development of a fiber-optic sensor based on surface plasmon resonance on silver film for monitoring aqueous media

A reliable fiber-optic SPR sensor based on silver is developed in this paper for chemical and biological applications. The range of measurable indices is shifted down by coating an overlay of zirconium acetate on the silver surface by sol–gel technique. The feasibility has been investigated in advance by theoretical analyses. The experimental fiber-optic sensor demonstrates its capability to operate in the aqueous media with the detectable range of refractive indices of 1.33–1.36. A self-assembled monolayer (SAM) of long chain thiol is introduced to cover the surface of silver in order to prevent silver from deterioration. Experimental studies demonstrate that in this way, the sensor lifetime increases from days to weeks. This work provides a base for developing an affinity biosensor.