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Coding metasurfaces have emerged as a promising venue for terahertz (THz) beam steering and beamforming. In this study, we designed a transmission metasurface with a complementary structure based on Babinet's principle. The beam-steering capability of the coding metasurface is implemented by encoding “0” and “1” elements with different phase responses and by controlling the coding sequences. The deflection angle can be controlled by changing the period of these 0 and 1 elements. Despite the development of beam-steering technology, measurements of the direction pattern of steered THz beams remain challenging. Systems for THz time-domain spectroscopy and spectral imaging are used to characterize the flexible coding metasurfaces. The THz imaging system can provide information on the directional pattern of the beam. To verify the performance of the proposed metasurface, the experimental measurements of beam deflection were found to be consistent with the values yielded by a simulation. Our study provides an effective platform for the design and measurement of THz beam steering.

Dynamic terahertz (THz) beam steering is a promising technique for numerous applications, including communication, high-resolution imaging, and radar. However, advances in this technology are considerably limited by inadequate broadband and active phase shifters at THz frequencies. In this paper, we developed a type of VO2-based device capable of broadband THz beam steering. The effect of the tunable Brewster angle of the VO2 thin film along with the insulator-to-metal transition process was verified. We demonstrated that the VO2 grating could realize a dispersive beam deflector in a broad frequency band. Furthermore, upon heating, the VO2 grating could switch between three states of mirror reflector, “rainbow” deflector, and metallic grating. We believe that the proposed reconfigurable and broadband THz beam deflector offers a powerful avenue for manipulating THz beams.

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