Lattice plasmons in dielectric nanoparticle arrays arranged on metal film

We propose a hybrid plasmonic photonic crystal consisting of a square array of dielectric nanoparticles arranged on a metal film with a gap inbetween. Simulations show that this plasmonic crystal supports lattice plasmon modes just like the metal nanoparticle array, exhibiting an extremely narrow and deep reflection dip. When interparticle spacing increases from 800 to 1000 nm, the full width at half the maximum of lattice plasmons decreases from 21 to 4 nm, and the lowest reflectance is close to zero. The resonant wavelength of this plasmonic crystal is highly sensitive to the local environment. It yields a sensitivity of 700 nm RIU−1 and a figure of merit of 33, which can be used in sensing of the refractive index.