Micro-cones Array-Based Plasmonic Metasurface for Sensitive and Enhanced Raman Detection

We report a micro-cone unit-based plasmonic metasurface for surface-enhanced Raman spectroscopy. The unit consists of Au cone-shaped needle, Au thin film, and SiO 2 substrate. To verify performance of the structure for surface-enhanced Raman scattering (SERS) detection, both theoretical and experimental studies are performed. Highly efficient coupling conditions satisfied by the structure, ∇Φ > k 0 , the metasurface can realize the SERS measurement with detection limit and analytical enhancement factor (AEF) as high as 10 −8 M and 10 9 , respectively. With concentrations of benzenethiol ranging from 10 −2 down to 10 −8 M, the ratio of Raman intensity I ω 2 / I ω 1 increases from 0.6 to 0.85 and I ω 3 / I ω 1 from 0.9 to 1.3. This structure can provide a new insight for biosensing and biochemistry analyses.