Refractive index sensing performances for single -metal and bimetallic Tamm plasmon configurations with an investigation of different structural configurations dependency

This paper presents a comparative study of optical Tamm plasmon (OTP) realized with single metal and bimetallic combinations. Different parameters of the structural configuration such as the dielectric thickness of the DBR constituents (d 1 and d 2 ), angle of incidence (θ) and suitable metal thickness (d m ) are investigated on the effect of realization of OTP formation. The sharpness of the resonance in terms of FWHM, quality factors for different combinations is evaluated for both single metal and bimetallic combination. With the background of the findings, we investigated the sensor applications of the two configurations with a spacer layer containing the sensing medium. The sensitivity (S n ) (whose unit is presented in standard form of nm multiplied by inverse of Refractive Index Unit (RIU)) of the two cases is almost equivalent with the peak value of ~ 180 nm/RIU with an average value of ~ 170 nm/RIU for the considered RI range. The detection accuracy (DA) for single-metal is higher resulting into better quality factor (QF) (297 vs. 247) than the bi-metallic configurations. Figure of merit (FOM) for single-metal is again higher with peak value of ~ 92 RIU −1 against 85 RIU −1 for bi-metal configurations. Amplitude sensitivity which corresponds to the change in reflectivity minima of the resonance wavelength presents almost identical nature for the two different types of sensors. Though DA, QF and FOM for single-metallic configurations are improved than bi-metallic one, however both the spectral and amplitude sensitivity are almost identical. Additionally, the performances are not drastically changed for the bi-metallic one where it can address the issues of the single-metal usage having oxidation and propagation losses. These findings will be of great help for future opto-electronic devices based on multilayer configurations.