Coupled planar silver nanoparticle arrays as refractive index sensors

The optical properties of plasmon coupled, planar silver nanoparticle arrays (PSNA) were studied as a function of the refractive index of the surrounding medium. The PSNA samples were fabricated by self-assembling 100 nm silver particles into a single layer on chemically modified glass substrates. The arrays exhibit an intense sharp peak in the extinction spectrum in the UV–vis spectral range originating from near-field interactions between localized surface plasmons in the nanoparticles. The spectral position of the peak appeared to be sensitive to changes in the dielectric function of the local surrounding medium. Because of this dependence, the PSNA can function as a sensor for measuring the refractive index of the host medium.