A high-sensitivity D-shaped photonic crystal fiber surface plasmon resonance sensor for low refractive index detection

In this paper, a highly sensitive surface plasmon resonance-based photonic crystal fiber sensor for low refractive index (RI) sensing and detection is proposed. To excite the surface plasmon polariton (SPP) mode, Au and TiO2 were coated on the top and bottom of the sensor in the shape of notched rings. The utilization of TiO2 has the potential to augment the interplay between the core and surface SPP modes, leading to an enhancement of the sensitivity of the sensor. The finite element method was applied for evaluating the sensor's performance. The attainment of optimal wavelength sensitivity of 21,500 nm/RIU and matching resolution of 4.65x10(-6) RIU was achieved through the refinement of structural parameters within the low RI detection range of 1.18-1.28. The findings of the study hold promise for potential applications in the fields of medical diagnostics and identification of low RI environments.