RT - Journal Article T1 - Refractive Index Sensing by a Narrow-Band Perfect Absorber based on Plasmonic Resonances JF - opsi YR - 2020 JO - opsi VO - 26 IS - 0 UR - http://opsi.ir/article-1-2197-en.html SP - 1093 EP - 1096 K1 - Meta-Insulator-Metal K1 - Narrow-band K1 - Plasmonic Perfect Absorber K1 - Refractive Index K1 - Biosensor AB - In this paper, a plasmonic perfect absorber based on the metal-insulator-metal structure has been designed as a biosensor. Simulation results performed by the 3D FDTD numerical method show that the absorption spectrum of the proposed biosensor has a narrow-band resonance peak in the wavelength range of 580-640 nm. After the perpendicular incidence of a plane wave light within wavelength range mentioned, the resonance wavelength shifts from λ=600.1 nm to λ=614.8 nm when the analyte refractive index increases from n=1 to n=1.1. The sensor,s sensitivity (S), full width at half maximum (FWHM) and the figure of merit (FOM) were obtained 147 nm/RIU, 9.6 nm, and 15.3, respectively. The analysis of the electric field at certain cross-sections of the absorber shows that the plasmonic resonances are stimulated at the insulator-metal and analyte-metal interfaces, and by amplifying the field at these surfaces, the sensing process is possible in the very small wavelength range. LA eng UL http://opsi.ir/article-1-2197-en.html M3 ER -