Plasmonic metasensors comprising gold nanodisks and prisms on SiO2 substrate in the near infrared regime

This study presents a theoretical comparative analysis of localized surface plasmon resonance (LSPR) sensors based on gold nanodisks and triangular prisms patterned on a silicon dioxide (SiO2) substrate, with the aim of advancing biosensing technologies operating in the near-infrared regime. While conventional surface plasmon resonance (SPR) techniques offer high sensitivity, they often suffer from complex fabrication processes and reduced performance in detecting large biomolecules. In this work, we investigate how geometric parameters - such as height, nanodisk diameter/triangle side, and periodicity - influence the optical response and sensitivity of the two nanostructured configurations. Simulation results reveal that prisms outperform nanodisks in terms of bulk refractive index sensitivity, reaching values up to 572 nm/RIU compared to approximately 289 nm/RIU for nanodisks. This enhanced performance is attributed to the sharper edges and corners of the prism geometry, which promote stronger electric field confinement and the formation of localized electromagnetic hot spots. Furthermore, the use of gold ensures chemical stability and biocompatibility in both cases, making the designs suitable for real-world biosensing applications. Overall, this work not only emphasizes the potential of triangular prism-based metasurfaces in simplifying sensor architectures and reducing costs but also provides a solid theoretical basis for future experimental validation and integration into practical biosensing platforms.