Highly Sensitive Plasmonic Biosensors with Precise Phase Singularity Coupling on the Metastructures.

In this paper, we demonstrated the ability of a plasmonic metasensor to detect ultra-low refractive index changes (in the order of ∆n = 10 RIU), using an innovative phase-change material, vanadium dioxide (VO), as the sensing layer. Different from current cumbersome plasmonic biosensing setups based on optical-phase-singularity measurement, our phase signal detection is based on the direct measurement of the phase-related lateral position shift (Goos-Hänchen) at the sensing interface. The high sensitivity (1.