Highly sensitive refractive index sensor based on Bloch surface waves with lithium niobate film

This paper demonstrates a novel Bloch surface wave (BSW) sensor with high sensitivity. A lithium niobate (LiNbO${}_3$) film is introduced on the top layer of SiO${}_2$/TiO${}_2$ one-dimensional photonic crystal. BSW resonance is excited by the Kretschmann prism. The rigorous coupled wave analysis method (RCWA) is used to conduct numerical simulation analysis of the designed BSW sensor. The wavelength and azimuth sensitivity of the designed sensor can reach 1522 nm/RIU and 646°/RIU, respectively, or even higher. The results reveal the potential application of LiNbO${}_3$ as a tunable material in the field of refractive index sensors for chemical and biological sensing.