Transmission of light through slits array in a metal-insulator-metal structure

Light transmission through slits array in a thin dielectric core layer sandwiched between two metallic cladding (MIM) is investigated using the finite-difference time-domain (FDTD) method. The dispersion relation of surface plasmon polariton (SPP) in the MIM structure is analyzed. The results show that SPP modes on the core layer act as a resonator-coupler, which helps to couple the resonance energy in the upper slit arrays to that in the lower slit arrays, and there is an enhanced transmission peak under appropriate resonance conditions. Coupling process is verified by the field profiles of the SPP modes calculated by FDTD method. Different MIM structures are designed to control the light transmission.