Highly sensitive dual-core symmetrical side-polished modified D-shaped SPR based PCF refractive index sensor with deeply etched micro openings

Abstract

A novel dual side-polished photonic crystal fiber (DSP-PCF) refractive index (RI) sensor is proposed for the RI detection range of 1.30−1.35. An active plasmonic metal gold (Au) is deposited on a polished flat fiber surface to generate plasmons so that it can detect the change in RIs of its surrounding medium. A thin titanium dioxide (TiO2) layer is coated to assist the adhesion of Au layer with silica-based fiber. To enhance the sensitivity, silicon nitride (Si3N4) is deposited on the top of Au to make it as a dielectric sensing layer. Simulation outcomes demonstrate that the maximum wavelength sensitivity (WS), amplitude sensitivity (AS) and RI resolution reach the highest value of 35,000 nmRIU−1, 350 RIU−1 and 4.347×10-6RIU, respectively, for DSP-PCF. Additionally, the obtained WS for DSP-PCF is far better than the recently reported PCF sensors in the above mentioned RI detection range to the best of our knowledge. With these significant outcomes over the wide analyte RI range, the proposed sensor opens new possible study windows in the field of organic chemicals and biological sensing.