Broadband and high-efficiency transmissive type nondispersive polarization conversion meta-device

Metamaterials with tailored electromagnetic properties hold great promise for the manipulation of electromagnetic waves. Here, we propose an intriguing off-resonance metadevice to control the polarization states and dispersive features of the electromagnetic waves simultaneously. The proposed meta-device is composed of stacks of bilayer gear-like metallic patterns, which exhibit significant anisotropy due to the geometric asymmetry. The results show that the considered meta-device operates in a transmission mode and can achieve broadband and nondispersive cross-polarization transmission with a high polarization conversion ratio nearly 100% for both of the normal incident linear and circular polarization waves. Moreover, the broadband and efficient polarization conversion behavior of the metadevice can be maintained regardless of the incident angle for the circular polarization waves. These fascinating performances enable the meta-device to act as an excellent half-wave plate being greatly beneficial for polarization manipulation.