We demonstrate a terahertz flat lens based on tri-layer metasurfaces allowing for broadband linear polarization conversion, where the phase can be tuned through a full 2p range by tailoring the geometry of the subwavelength resonators. The lens functionality is realized by arranging these resonators to create a parabolic spatial phase profile. The fabricated 124-μ m-thick device is characterized by scanning the beam profile and cross section, showing diffraction-limited focusing and ~68% overall efficiency at the operating frequency of 400 GHz. This device has potential for applications in terahertz imaging and communications, as well as beam control in general.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics