Surface plasmon resonance sensor based on gold-coated hollow fiber structure

Abstract

A hollow fiber (HF) surface plasmon resonance (SPR) sensor based on the gold-coated HF is proposed. Different from previous HF SPR sensors, gold is adopted as the thin metal layer material instead of silver. Because gold is much more stable than silver, the durability and scope of the application of the proposed HF sensor are improved. The thin gold film is uniformly coated on the inner wall of the HF by the chemical solution deposition technique. The proposed sensors with different gold layer thickness are fabricated. The transmission spectra of the fabricated sensors filled with liquid of different refractive index are measured. Experimental analyses were carried out to evaluate the performances of the sensors, such as sensitivity and figure of merit (FOM). The highest experimentally achieved sensitivity and FOM are 7054 nm/RIU and 92 RIU^-1, respectively. Compared to the silver coated HF SPR sensor, it has much narrower resonance dip and thus higher FOM, which indicates that the coated gold layer is more uniform than the silver layer. The technique of coating uniform gold film in the hollow core of optical fibers has potential in the research of the other optical fiber sensors.