Highly sensitive D-SPR sensors with optimized metallic thin films for bio-analyte detection.

Ehiabhili, John; Prabhu, Radhakrishna; Kannan, Somasundar

Abstract

There is a growing need for precise and rapid detection methods in fields such as biomedical diagnostics, environmental monitoring, and chemical analysis. Surface plasmon resonance (SPR) sensors have been used for the detection and quantification of a wide range of analytes, including biomolecules, chemicals, and gases, in real-time. Despite the promising capabilities of SPR sensors, there remains a gap in creating a balance between having a large enough area to capture a significant number of analytes for detection and being small enough to ensure high sensitivity. This research aims to explore the design of a D-shaped SPR-based optical fiber sensor, focusing on the use of copper, gold, and silver thin films at optimized width and thickness of 10 μm and 45 nm, respectively, to improve the sensor's performance. Employing a computational approach, this study examines the influence of the optimized width and refractive indices of metallic films on the sensor's characteristics. The 10 μm width of the metallic thin film has been found to produce an optimal balance between the sensitivity and the dynamic range of the sensor. Leveraging on the ratio of the real and imaginary parts of the dielectric constant of the thin film metal provides insight into the optical properties and sensitivity at certain wavelengths. Within an analyte refractive index range of 1.37–1.42 and a wavelength range of 650–1200 nm, results indicate that silver outperforms gold and copper at the optimized width with a wavelength sensitivity, and detection accuracy of 12,300 nmRIU−1, and 3.075, respectively. By optimizing the width of the metal thin film at 10 μm, a highly sensitive D-SPR is designed, allowing for enhanced sensor detection capabilities for a wide range of bioanalytes.

Citation

EHIABHILI, J., PRABHU, R. and KANNAN, S. 2024. Highly sensitive D-SPR sensors with optimized metallic thin films for bio-analyte detection. Photonics [online], 11(8), article number 764. Available from: https://doi.org/10.3390/photonics11080764

• Journal Article Type: Article
• Acceptance Date: Aug 13, 2024
• Online Publication Date: Aug 15, 2024
• Publication Date: Aug 31, 2024
• Deposit Date: Aug 16, 2024
• Publicly Available Date: Aug 16, 2024
• Journal: Photonics
• Electronic ISSN: 2304-6732
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Issue: 8
• Article Number: 764
• DOI: https://doi.org/10.3390/photonics11080764
• Keywords: Surface plasmon resonance; D-shaped sensor; Metal thin film; Sensitivity; Optical fibre; Analyte detection
• Public URL: https://rgu-repository.worktribe.com/output/2434526