Improved Sensitivity of a Sensor Based on Metallic Nano-cylinder Coated with Graphene

• Published in: Plasmonics (Norwell, Mass.) Vol. 19; no. 4; pp. 2053 - 2060
• Main Authors: Hedhy, Manel, Ouerghi, Faouzi, Zeng, Shuwen, AbdelMalek, Fathi
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2024; Springer Nature B.V; Springer Verlag
• Subjects: Biochemistry; Biological and Medical Physics; Biological properties; Biomolecules; Biophysics; Biosensors; Biotechnology; Chemistry; Chemistry and Materials Science; Crystal defects; Cylinders; Electric fields; Engineering Sciences; Graphene; Measuring instruments; Nanotechnology; Optical properties; Optics; Photonic; Photonic crystals; Plasmonics; Polaritons; Real time; Refractivity; Sensitivity enhancement; Sensors; Biomolecules; Graphene nano-cylinder; Surface plasmon; High sensitivity; surface Plasmon. I; High sensitivity biomolecules graphene nano-cylinder surface Plasmon. I; graphene nano-cylinder; biomolecules
• DOI: 10.1007/s11468-023-02139-7
• ISSN: 1557-1955

This paper introduces a highly sensitive biosensor based on a plasmonic nanostructure-enhanced resonance effect. The sensor exploits a hexagonal photonic crystal composed of plasmonic nano-cylinders, including a graphene nano-cylinder as a defect, which can considerably increase the concentration of electric fields. This amplification enables the detection of tiny variations in refractive indices linked to a laser source for plasmonic excitation. Each defect consists of a hollow metallic cylinder surrounded by graphene, all within a metallic matrix. During the sensing process, surface plasmon polaritons interact with the core-guided modes of the patterns, which are subsequently filled with the analytes to be measured. The nano-cylinders’ width is optimized to take advantage of their unique optical properties in nanoscale confinement, resulting in high sensitivity. The sensor achieves an impressive sensitivity of 17,750 nm/RIU (refractive index unit) and a FoM of 2218 (RIU −1 ) for n  = 1.456 at the optimum value of Δ R  = ( R out  −  R in ) = 200 nm. These metallic cylindrical channels exhibit distinct responses to different analytes across a wide range of Δ R , enabling simultaneous detection of various types of biomolecules. These exceptional properties make the sensor suitable for a broad range of applications, including real-time chemical and biological sensing. Furthermore, it offers the potential to create compact devices for measuring different refractive indices.