Theoretical investigation of absorption and sensitivity of nano-plasmonic fiber optic sensors

In this paper, fiber-optic sensor based on surface plasmon resonance (SPR) is considered. The fiber-optic sensor is coated with thin nanoparticle metallic films. The nanoparticle metallic film consists of spherical metallic nanoparticles embedded in a host material. It is shown that sensitivity and absorption of sensor depends on number and type of films. It theoretically analyzed that the different states such as, fiber-optic sensor with a single thin layer of spherical gold or silver nanoparticle and a bimetallic arrangement of silver and gold nanoparticles. It also studied dependence of the sensitivity and absorption of sensor on the parameters such as gold particle size, film thickness, refractive index of host material, sensing region length, fiber core diameter, maximum absorption wavelength, half maximum width of the sensing medium and background refractive index of the sensing layer.

► The sensitive increase for any value of the L/D   with increasing of concentration. ► The Ptransmax increases but the Sn decrease with increasing of the film thickness. ► Whenever the particle size decreases, Ptransmax decreases the Sn increases. ► Sn is increased for samples with increase of maximum absorption wavelength. ► Sn is increased for samples with increase of width of the absorption spectrum.