Efficient manipulation of terahertz waves by multi-bit coding metasurfaces and further applications of such metasurfaces*

Benefiting from the unprecedented superiority of coding metasurfaces at manipulating electromagnetic waves in the microwave band, in this paper, we use the Pancharatnam-Berry (PB) phase concept to propose a high-efficiency reflective-type coding metasurface that can arbitrarily manipulate the scattering pattern of terahertz waves and implement many novel functionalities. By optimizing the coding sequences, we demonstrate that the designed 1-, 2-, and 3-bit coding metasurfaces with specific coding sequences have the strong ability to control reflected terahertz waves. The two proposed 1-bit coding metasurfaces demonstrate that the reflected terahertz beam can be redirected and arbitrarily controlled. For normally incident x-and y-polarized waves, a 10 dB radar cross-section (RCS) reduction can be achieved from 2.1 THz to 5.2 THz using the designed 2-bit coding metasurface. Moreover, two kinds of orbital angular momentum (OAM) vortex beams with different moduli are generated by a coding metasurface using different coding sequences. Our research provides a new degree of freedom for the sophisticated manipulation of terahertz waves, and contributes to the development of metasurfaces towards practical applications.

Automated summary

This paper proposes a high-efficiency reflective-type coding metasurface that can manipulate the scattering pattern of terahertz waves and implement novel functionalities using the Pancharatnam-Berry (PB) phase concept. By optimizing coding sequences, the designed metasurfaces demonstrate strong control over reflected terahertz waves. The research provides a new degree of freedom for manipulating terahertz waves and contributes to the practical applications of metasurfaces.