High Performance Titanium Oxide Coated D-Shaped Optical Fiber Plasmonic Sensor

A highly sensitive D-shaped optical fiber refractive index sensor based on surface plasmon resonance is designed and analyzed by using numerical simulations based on the finite element method. The flat surface of the fiber is coated with a gold layer that works as the plasmon active metal, followed by a titanium oxide (TiO
₂
) layer, which is employed to enhance the performance of the sensor. The results demonstrate that the proposed sensor's properties highly depend on the metal and dielectric coating's thickness, enabling the tuning of the resonance wavelength. By supposing the system noise to be 0.1 nm, the theoretical maximum sensitivity was found to be 30000 nm/RIU, with a resolution of 3.33×10
^-6
RIU and a figure of merit (FOM) of 312.46 RIU
^-1
, for an analyte with a refractive index of 1.41. The sensor's sensitivity and FOM is improved upon the state of the art, possibly opening new windows of study in the fields of biological and chemical sensing.