Development of Specialty Optical Fiber Incorporated with Au Nano-particles in Cladding for Surface Plasmon Resonance Sensors

A specialty optical fiber incorporated with Au nano-particles (NPs) in the cladding has been developed by modified chemical vapor deposition process for surface plasmon resonance (SPR) sensor applications. The cladding width and the diameter of the fabricated fiber were 2.6 μm and 124.3 μm, respectively. The incorporation of Au NPs in the cladding of the fiber preform with the average diameter of ~ 3.8 nm was confirmed by TEM and by the Raman bands appeared at 1017 to 1220 cm-1, 1243 cm-1 and 1304 cm-1. Absorption peaks of the fiber preform and the fiber appearing at 585 nm and 428 nm, respectively were due to surface plasmon resonance (SPR) of the incorporated Au NPs. The measured peak wavelength of the SPR was found to increase from 480.9 nm to 505.5 nm with refractive index (n) from 1.406 to 1.436 and the SPR sensitivity was estimated to be 820 nm/RIU