Numerical investigation of surface plasmons associated subwavelength optical single-pass effect

Surface plasmons (SPs) associated optical single-pass effect has been investigated in novel subwavelength metallic structures, including single slit and grating structures. With influence of SPs, these metallic structures can enhance transmission in incident direction and suppress it in the opposite direction, exhibiting a single-pass effect. The finite difference time domain method is employed to study the influences of structure parameters on far-field transmission, near-field electric held distribution and extinction ratio of the single-pass transmission effect. A maximal extinction ratio of 47.83 dB is achieved in the grating structure.