Liquid Crystal Metasurface for On-Demand Terahertz Beam Forming Over 110° Field-Of-View

The terahertz spectral region, which bridges between electronics and optics, is poised to play an important role in the development of transformative wireless communication and imaging systems with unprecedented functionality. Currently, a major challenge in terahertz technology is to develop high-performance terahertz beam-forming devices that can dynamically shape the terahertz radiation in a flexible manner. Existing terahertz beam-forming devices have limited coding bits, field-of-view, and beam gain. Here, a reconfigurable liquid crystal-integrated terahertz metasurface is experimentally demonstrated, with each metasurface unit cell being independently addressable. The metasurface has a 260° continuous phase tuning range with a liquid crystal layer thickness of only 1% of the free-space wavelength. The terahertz wave diffracted from the metasurface can be steered toward a wide range of directions is shown, covering a record-large 110° field-of-view with a peak gain of 25 dBi. The metasurface also features a low power consumption and sub-second switching time. Furthermore, the formation of multiple terahertz beams is demonstrated, with the direction of each beam and the power ratio between beams adjustable on demand. The proposed liquid crystal metasurface possesses compelling prospects for future terahertz communication and imaging applications.