A dual-band programmable metasurface for terahertz beam steering

Terahertz programmable metasurfaces hold significant promise for next-generation communications due to their capability to steer electromagnetic waves. However, most existing terahertz metasurfaces operate at only a single frequency, leaving much of the vast terahertz spectrum underutilized. In this study, we introduce a “butterfly” programmable dual-band metasurface, integrated with liquid crystals, designed for efficient terahertz beam steering. By applying bias voltages, the metasurface achieves a phase change of nearly 270° at two distinct frequencies, ∼400 and ∼700 GHz. Our experimental results demonstrate that the butterfly metasurface is compatible with both binary and ternary coding schemes at these frequencies, remarkably enhancing beam-steering performance and expanding spatial coverage. This advancement in dual-band metasurface technology marks a step forward in harnessing the full potential of the terahertz spectrum, opening another pathway for broadband terahertz communication and imaging applications.