Refractive index sensor based on silica microfiber doped with Ag microparticles

We proposed a composite microfiber using silica capillary and Ag microparticles, and demonstrated its optical sensing characteristics by changing the refractive index of surrounding environment using different concentrations of NaCl solution. Either the diameter or doping density of Ag microparticles contributes to the sensitivity change. The experimental results reveal that the diameter uniformity and distribution of Ag microparticles exerted impact on the sensing performance. The highest sensitivity of −7246 dB/RIU has been experimentally demonstrated in this work. The selectivity of this composite microfiber sensor will be explored by decorating its surface with some enzyme or other sensitive materials.