Polarization modulation terahertz filter based on metallic fractal structures

In this paper, the terahertz transmission properties of metallic fractal structures are presented by the terahertz time domain spectroscopy and the numerical analysis based on the finite differential time domain simulation. Several metallic fractal structures including the H-shape fractal pattern and the square-hole fractal pattern are studied. The terahertz transmission spectra of these metallic fractal structures are shown at two polarization of terahertz field perpendicularly. The results show that the asymmetric metallic fractal structures such as H-shape fractal structure have an obvious polarization dependent and frequency selective transmission. The symmetric structures have no such polarization dependence. Terahertz transmission through the H-shape metallic fractal structure can be switched between the different pass bands by changing the polarization direction of terahertz field relative to the first-level fractal line. Therefore, a potential application may be to realize a polarization tunable terahertz filter based on this kind of H-shape metallic fractal structure.