A polarization and angle insensitive terahertz lens based on cascaded complementary metasurfaces

In this paper, a three-layer cascaded complementary metasurfaces for complete terahertz (THz) phase control was designed at 3.11 THz. On this basis, a transmissive lens was fabricated and experimentally demonstrated with a focal length of 23 mm and a full width at half maximum (FWHM) of 1.1 mm at the focal plane. Simulations and calculations reveal that the lens is insensitive to incident angle and polarization direction, which is favorable for the development of compact THz imaging and spectroscopy systems.