Analysis and simulation of surface plasmon resonance in tantalum pentoxide and gold layers on a prism

The small sensors are widely used and became important in our lives. Therefore, the simulation of these sensors is vital and save money and time. In this study, an SPR sensor was simulated for refractive indices and a wide range of wavelengths. The new suggested sensor employed the otto configuration, using Tantalum Pentoxide (Ta₂O₅) dielectric with a variable thickness (0–100 nm) and a gold (Au) with 50 nm thickness, deposited on a prism. The sensing medium of the sensor is gas, including air and various refractive indices (Δn = 0, 0.04), to consider different gas cases. The study covered a wavelength light range from 100 to 1000 nm. The results revealed that the strongest SPR appeared in the infrared range (IR), specifically between 900 and 1000 nm, while it was less pronounced in the visible range and absent in the ultraviolet region. The sharpest and longest SPR dip occurred in the IR, with a smallest value of full-width half maxima (FWHM) with 0.2° at Ta₂O₅ for the thickness from 0 to 100. The longest SPR dip is 0.96° at Ta₂O₅ for the thickness 40 nm. Consequently, the suggested SPR sensor had better detection accuracy and sensitivity in the IR region.