Ultrathin metasurfaces generate multiform beams (electromagnetic, multi-direction, multi-polarization, multi-frequency, and multi-beam) with promising applications in numerous optical traps, modern communication systems, and complex environments identification. However, their capacity to generate required multiform beams concurrently limits their application.
Researchers developed a multifunctional surface with a polarization selection structure and integrated electric and magnetic systems to overcome the primary challenge with the multiform beams. It consists of three weakly coupled layers that can produce various quasi-nondiffracting beams. The top and bottom layers are surfaces that reflect two different incident waves, resulting in two forms of quasi-non-diffracting rays. The middle layer, a transmissive surface that can transmit another incident wave, generates the third type of quasi-non-diffracting beams.
The researchers produced and tested the surface for verification. According to the results of a full-wave simulation and observations, the proposed surface could generate three different types of quasi-non-diffracting beams.