Plasmonic gold nanodiscs using piezoelectric substrate birefringence for liquid sensing.

This article presents the simulation, fabrication, and experimental characterization of a surface plasmonic resonance (SPR) sensor integrated with an acoustic sensing compatible substrate. The SPR sensor is designed to work in the visible region with gold nanodisc arrays fabricated on LiNbO₃, which is both piezoelectric and birefringent. A linear relationship between resonance wavelength and varying liquid refractive indices were observed in experiments, and a sensitivity of 165 nm/refractive index unit was obtained. Polarization effects of the birefringent property of the Y-cut LiNbO₃ substrate have been investigated, which can also be applied to X-cut LiNbO₃. Our study demonstrates the feasibility of an SPR sensor device utilizing a birefringent substrate, which has acoustic wave compatibility and can pave the way toward much more robust and flexible biosensing devices. [ABSTRACT FROM AUTHOR]