Refractive index sensing using a linear graded plasmonic chain of metal nano-particles

We study the transmission efficiency of optical signals through a graded linear chain of spherical silver nano-particles placed parallel to a silver substrate by using the Green's function formalisms and the dipole approximation. A sensor based on plasmon resonance shifts is also discussed. The obtained spectral sensitivity is more than 273.17 nm/RIU in the visible light region, which makes such a structure an excellent candidate for liquid detection.