Propagation velocity modulation and electromagnetic energy concentration of guided wave on corrugated metal surface

Corrugated metal surface is proposed to modulate the modal properties of surface plasmon polariton (SPP). It is found the propagation velocity of SPP wave can be considerably altered by introducing surface corrugations. Both cases of shallow corrugations and deep corrugations are investigated. The results show that a shallow corrugation can modulate the wave propagation in a weak manner, but a deep corrugation can strongly change the dispersion curve shape and lead to the coexistence of waveguide mode, zero-group-velocity and mode cutoff. These unique properties are utilized to control mode propagation velocity and concentrate electromagnetic energy.