An array structures of nanoparticle-coupled hyperbolic metamaterials for efficient SERS sensing

Hyperbolic metamaterials (HMMs) have been employed in the field of surface-enhanced Raman scattering (SERS) for their properties to support large-wave vector bulk plasmon polariton (BPP) waves, whereas the excitation of BPP is challenging to a certain extent. In addition, with the advance of SERS, the substrate for energy utilization has aroused increasing attention. An HMM-Ag nanoparticles (Ag NPs) platform based on patterned sapphire substrate (PSS) array structure was proposed in this study. With Ag NPs as the external coupling structure, the generated large-wave vector scattered light excited the BPP in the HMM and extended the energy into the Ag NPs gap. On that basis, a hot surface with a high density of "hot spots" was formed. PSS with excellent light trapping capability was employed as a substrate, which improved the energy utilization of the platform. Furthermore, the good hydrophobicity of the nanoparticle array structure further amplified the SERS signal. Lastly, the excellent performance of the platform was experimentally verified, the detection limits of CV and R6G reached 10-10 M and 10-11 M, respectively. Accordingly, it is believed that the plasma platform has promising applications in high-sensitivity sensing and biochemical detection.