title: Achromatic wave plate in THz frequency region based on parallel metal plate waveguides with a pillar array.
abstract: We demonstrated an achromatic wave plate based on parallel metal plate waveguides in the high THz frequency region. The metal plates have periodic rough structures on the surface, which allow slow transverse magnetic wave propagation and fast transverse electric wave propagation. A numerical simulation showed that the height of the periodic roughness is important for optimizing the birefringence. We fabricated stacked metal plates containing two types of structures by chemical etching. An array of small pillars on the metal plates allows higher frequency optimization. We experimentally demonstrated an achromatic quarter-wave plate in the frequency region from 2.0 to 3.1 THz.
authors.forename: Masaya
authors.initials: M
authors.lastname: Nagai
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Mukai
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Minowa
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ashida
authors.forename: Takehito
authors.initials: T
authors.lastname: Suzuki
authors.forename: Jun
authors.initials: J
authors.lastname: Takayanagi
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ohtake