The fiber surface plasmon resonance sensor based on TiO2 /Au-NPs sensitization

The fiber Surface plasmon resonance (SPR) sensor based on titanium dioxide(TiO) and Au nanoparticles (Au-NPs) sensitization is offered as a practical means of increasing the sensitivity and figure of merit (FOM). Through finite element simulation and experimental testing, it is found that in TiO with high dielectric constant and high dielectric conductivity, the carrier movement is fast and consumption is low, which enhances the photocurrent signal and leads to charge redistribution, thus enhances the electric field; while the Au-NPs will stimulate the stronger Localized Surface plasmon resonance (LSPR) phenomenon, and both of them will undergo electric field resonance coupling. The sensitivity of the sensor is higher because its surface electric field is 3.67 times stronger than the conventional Au film sensor. When exposed to external conditions, the sensitivity can reach 9715 nm/RIU within the refractive index (RI) at 1.33213–1.34055, which is 4.69 times higher than a conventional Au film sensor. The FOM can reach 57.8 RIU, which is 2.05 times higher than the conventional Au film sensor. In addition, TiO and Au-NPs on the surface of the sensor are less prone to collapse, and the stability test results show that the relative standard deviation (RSD) is 0.5929 %, which exhibits good reliability and stability. The structure of the sensor is very simple, relatively easy to fabricate, and has good applicability in the field of biochemical testing.