Abstract
In this work, a surface plasmon resonance (SPR) sensor based on a novel liquid-core polymer optical fiber (POF) is proposed and numerically analyzed for refractive index (RI) detection. The polytetrafluoroethylene (PTFE) fiber is selected as the platform for SPR sensing. We combine the PTFE-based POF with the liquid-core structure by introducing a hole filled with analyte into the fiber center. The hole also acts as the fiber core to guide the incident light. This design helps to realize the detection of solutions with low RI values (around 1.33), while keeping the distinguished sensing characteristics of the liquid-core structure. Two side air holes are introduced into the cladding and a thin silver film protected by a titanium dioxide layer is plated on the wall of one air hole, which helps to control the mode coupling. In order to optimize the design of this sensor, the impacts of parameters such as metal layer thicknesses and the central hole radius are investigated using the full-vector finite element method (FEM). After optimization, our design shows a wavelength interrogation sensitivity reaching up to 16,750 nm/RIU and an average full-width at half-maximum (FWHM) of 42.86 nm in the RI range of 1.325–1.35.
Highlights
When electromagnetic waves and density waves from free electrons at the metal–dielectric interface become coupled, a so-called surface plasmon resonance (SPR) is stimulated, generating the surface plasmon polariton (SPP), which is extremely sensitive to the surrounding refractive index (RI)change
The properties of the SPR sensor based on a novel liquid-core polymer fiber are numerically investigated and discussed in this paper
Two side air holes are introduced into the cladding of the PTFE-based polymer optical fiber (POF) to manipulate the resonance
Summary
When electromagnetic waves and density waves from free electrons at the metal–dielectric interface become coupled, a so-called surface plasmon resonance (SPR) is stimulated, generating the surface plasmon polariton (SPP), which is extremely sensitive to the surrounding refractive index (RI)change. A variety of SPR sensors have been proposed for environmental RI detection, which can be mainly divided into prism-based [5,6,7] and optical-fiber-based [8,9,10] designs. Optical-fiber-based SPR sensors possess the advantages of miniaturization, low cost, as well as high sensitivity. The key point in the design of such sensors is to ensure interaction between the photons and the surface electrons. For this purpose, commonly applied methods include partly or wholly removing the cladding [12,13] and depositing a metal film on the polishing surface, which can lead to leakage of the core mode energy and generation of the SPR
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
