High-sensitivity surface plasmon resonance sensors utilizing high-refractive-index silver nanoparticle sheets

We propose an idea for improving the angular sensitivity of Kretschmann-type surface plasmon resonance (SPR) sensors through the use of highrefractive-index silver nanoparticle (AgNP) sheets on metal substrates. According to Fresnel simulations, the angular sensitivity will be improved threefold by using the multilayered AgNP coating on gold or silver substrates. We confirmed the validity of this method by a model measurement with a SiO2 sputtered film, which has a refractive index similar to that of organic or biological molecules. This simple technique will contribute to realizing a high-sensitivity SPR sensor, especially for the detection of small molecules. © 2014 The Japan Society of Applied Physics