Broadband high-efficiency transmission asymmetry by a chiral bilayer bar metastructure.

A chiral metallic metastructure composed of bilayer twisted bars is proposed to realize a broadband asymmetric transmission for linearly and circularly polarized incident light, aimed at sustaining high efficiency of unidirectional polarization conversion over the whole operation band. Such a one-way propagation results from the chiral structural arrangement that destroys the rotational and translational symmetries in all directions. Moreover, its ultra-broad bandwidth, mainly depending on the bar length, originates from the subwavelength plasmon coupling between long- and shortbar dipole-like responses. The efficient broadband one-way characteristic exhibits a structure with promising prospects for metadevices capable of unidirectional polarization conversion manipulation. [ABSTRACT FROM AUTHOR]