Microstructure optical fiber based plasmonic refractive index sensor

This work proposes a highly sensitive plasmonic sensing scheme on a simple circular lattice microstructure optical fiber (MOF) structure. The proposed sensor performance is evaluated by using the finite element method (FEM) in the presence of perfectly matched layer (PML) and scattering boundary conditions. The highest amplitude sensitivity of 1582.95 RIU−1 and wavelength sensitivity of 11,000 nm/RIU is gained using amplitude interrogation and wavelength interrogation method, respectively, for the proposed device. In addition, the maximum sensor resolution of 9.09 × 10−6 RIU is obtained and the suggested sensor gives the same sensing performance for both x- and y-polarized modes due to its symmetrical structure, hence, capable to identify any analyte having refractive index (RI) from 1.34 to 1.40. Moreover, the value of the coefficient of determination (R2 = 0.9926) of the resonance wavelength is achieved close to unity using the quadratic curve fitting. Due to having these promising results, the proposed RI sensor can be useful in the area of bio-sensing.