Abstract

It has been demonstrated that, in the terahertz (THz) waveband, disk scattering slab modes (DSSMs) can exist in a heterostructure composed of a metallic subwavelength disk array coated on one surface of a dielectric slab. By observing the THz reflection spectrum it is found that DSSMs can transition into another category of confined modes, namely disk scattering modes (DSMs), when the slab is sufficiently thick relative to the THz pulse wavelength. Based on experimental measurements and theoretical analysis via a dipole-scattering model developed here, it is shown that the features of DSMs can be tuned by changing the geometric parameters of the disk array. These results are important for the design of new THz devices, such as THz filters.

© 2014 Optical Society of America