Finite-difference time-domain (FDTD) method is employed to study the optical properties of a novel kind of periodic subwavelength hole arrays composed of Tai-chi-shaped holes in silver film, and the optical transmission properties of femtosecond optical pulse excitation is numerically calculated. We find that this Tai-chi-shaped device has better optical band-pass filtering properties, such as narrower pass band and higher transmissivity in visible wavelengths range, than other devices under consideration. Based on the generation of surface plasmons resonance mode in the dielectric-metal inter...
