Broadband enhanced transmission in a film-array plasmonic structure through the plasmon coupling effects

Enhanced optical transmission in metal structures has received much attention due to the interesting physics and important applications in optoelectronic devices. Here, we propose and demonstrate the broadband enhanced optical transmission of a cooperative plasmonic structure consisting of double SiO2 films inserted with double parallel nanoparticle arrays composed of metal and dielectric spheres by the three-dimensional finite-difference time-domain (FDTD) method. Based on the bright mode and dark mode rule, the proposed structure shows a greatly enhanced broadband transmission through the hybridization of the plasmon resonant coupling effects of adjacent metal spheres, the surface plasmon waves at the interface between the metal array and the dielectric material and the optical cavity modes formed by the double dielectric films. The full width at half maximum (FWHM) of this broadband optical transmission with a highest transmission up to 85% is more than 400 nm. The broadband optical transmission can be efficiently tailored by varying the lattice period of the arrays and the distance between the metal and dielectric arrays. This proposed structure with subwavelength size may provide potential applications in optoelectronic devices such as broadband transparent and conductive devices, slow light devices, and highly sensitive sensors.