Highly sensitive based on a Mach-Zehnder interferometer with double-slot hybrid plasmonic waveguide

Abstract

A refractive index sensor based on the Mach-Zehnder interferometer (MZI) with double-slot hybrid plasmonic waveguide is proposed. Numerical simulation shows that the dispersion turning point (DTP) will appear when the group effective refractive index equals zero and ultra-high refractive index sensitivities can be achieved around the DTP. By changing the surrounding refractive index (SRI), the sensitivity can reach 120,000 nm/RIU with the SRI ranging from 1.0000 to1.0004 and 40,000 nm/RIU with the SRI ranges from 1.3330 to 1.3334. More importantly, the unique dual interference dips around the DTP double the sensitivity. Finally, by taking advantages of the exceptional refractive index sensitivity, we demonstrate a pressure sensor with sensitivity of 800 nm/MPa.