Exploring the properties of higher-order Tamm plasmons for liquid and gas detection

In this study, we present a numerical analysis of the higher-order Tamm plasmons for the design of a gas and liquid sensor. These plasmons are induced by a structure consisting of a cavity placed between the SiO2/Si3N4 Bragg grating and a finite layer of gold. This configuration is excited without the use of a coupling system and at normal incidence. The coupling of Tamm plasmons to the cavity generates narrow mode, resulting in high sensitivity to the refractive index of the environment due to the energy confinement. This grants the structure high sensitivity, reaching S = 900nm/RIU for gases and S = 640nm/RIU for liquids, with quality factors of 1025 and 1070, respectively.