Effects of a one-dimensional surface defect on designer surface plasmon polaritons

By using a finite difference time domain (FDTD) method, the effects of a one-dimensional (1D) surface defect on designer surface plasmon polaritons (designer SPPs) supported by a 1D metallic grating in THz domain are investigated. When the size of the defect is in a special range which is not too large, the designer SPPs reflected and scattered by the defect are weak enough to be neglected. The defect only induces a disturbance in the energy distribution of the designer SPP supported by the whole defect grating. If the defect size exceeds the said range, the reflecting and scattering are dominant in the influences of the defect on designer SPPs. Our analysis opens opportunities to control and direct designer SPPs by introducing a 1D defect, especially in low frequency domain. (condensed matter: electronic structure, electrical, magnetic, and optical properties)