High Sensitivity Sensors Based on Slit Plasmonic Gold Nanoantennas

In this research work, a novel model is used to analyse the propagation of Surface Plasmon Polaritons and the Extraordinary Optical Transmission effect. The model is based on generalised Fresnel Coefficients and wave-particle dualism. An oriented-object program is developed in Python to implement the model. This novel model brings geometrical intuition to complex electromagnetic problems and taking advantage of that, two kinds of sensors are designed at nano-scale and femtoseconds orders. Furthermore, by combining the working principles of both sensors, it is analysed if more sensitive ones may be designed. A gold nanoantenna is analysed as a tilt angle sensor in a 1.33–1.35 analyte, being concluded that angles are distinguished by analysing the optical intensity on the detected, which has variations between 2–10%. On the other hand, the gold nanoantenna is also able to monitor refractive index variations between 1.33 and 1.35. Sensitivities between 50–100%/RIU are obtained and it is concluded that by tilting the emission angle the sensitivity to the refractive index variation may be tuned.