Resonant terahertz transmissions through metal hole array on silicon substrate

We have observed resonant terahertz transmission peaks in samples comprising perforated periodic hole array in a metal film, covered with a high dielectric substrate. These resonant transmissions arise from the interplay between waveguide modes in dielectric substrate and the periodic hole array in the metal film. Finite difference time domain (FDTD) simulations show good agreement with the data, in support of the proposed mechanism. Inducing additional resonant transmissions using guided modes can lead to the ease in tuning the transmission peak frequencies that are potentially useful to terahertz (THz) bio-sensing.