Adjusting gap plasmon transmission and intensity in metal-insulator-metal waveguide

摘要

A device capable of adjusting gap plasmon (GP) transmission and intensity is proposed. The structure consists of two metallic films: one is etched with a nanoslit, and the other below is movable. Between them is a horizontal air channel. Numerical simulations show that the GP sources can produce alternatively in ports A and B when the film below is moved together with a groove in the center; thus, a sawtooth-like waveform is observed, which is different from the sine-like case without a groove and can be explained well by Fourier series. In addition, with the optimized length of film below, the source intensity can be further enhanced for Fabry–Perot resonance producing in both channels A and B.