Cross-Comparison of Surface Plasmon Resonance-Based Optical Fiber Sensors With Different Coating Structures

• Published in: IEEE sensors journal Vol. 12; no. 7; pp. 2355 - 2361
• Main Authors: Jie Cao, Galbraith, E. K., Tong Sun, Grattan, Kenneth T. V.
• Format: Journal Article
• Language: English
• Published: IEEE 01.07.2012
• Subjects: Aspect ratio; Coatings; Gold; gold nanorod; localized surface plasmon resonance (LSPR); optical fiber sensor; Optical fiber sensors; Optical fibers; Plasmons; Refractive index; surface plasmon resonance (SPR); Surface treatment
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2012.2188713

In this paper, optical fiber sensors, based on both surface plasmon resonance (SPR) and localized SPR (LSPR) approaches, have been successfully developed and cross-compared. The SPR sensor has been constructed by coating a thin layer of gold film on a piece of an optical fiber with the cladding having first been removed. Several LSPR sensors, however, have been configured in a slightly different way through coating several unclad fibers, each with a thin layer of gold-nanorods (GNRs) with a different aspect ratio. Subsequently, both SPR and LSPR sensors are exposed to solutions with different refractive index and their corresponding plasmon resonance wavelength shifts have been recorded and cross-compared. The experimental results obtained confirm that the SPR sensor has demonstrated a much higher sensitivity than that of any of the LSPR sensors, irrespective of the variation of the aspect ratio of GNRs coated. The LSPR sensors, however, have demonstrated a much better linearity compared to that of the SPR sensor.