Spectral properties of very deep zero-order metallic gratings with subwavelength slits at THz frequency region

Abstract

To study the reflection and transmission properties of the gratings, a novel system based on terahertz time domain spectroscopy was established. With this system, we have synchronously measured both the reflection and transmission spectra of the deep zero-order grating with subwavelength slits. In the experiments we found that the enhanced transmission spectra of the grating are complementary to the reflection spectra, which strongly depend on the geometry of the sample and the grating pose relative to the incident THz radiation, such as leaning from incident THz radiation and slits direction of the gratings out of p-polarized radiation. The experimental results agree with the theoretical analysis based on the surface plasmon polaritons and waveguide theory.