The coding metasurface integrated with tunable materials offers an attractive alternative to manipulate the THz beam dynamically. In this work, we demonstrate a THz programmable metasurface based on liquid crystal. The phase profile on the metasurface could be dynamically manipulated by switching the “0” and “1” states of each element. The programmable metasurface could deflect the THz beam using the designed coding sequence, and a maximum deflection angle of 32° has been achieved. The presented design opens a route of beamforming for THz communication.

Reconfigurable intelligent surfaces (RISs) play an essential role in various applications, such as next-generation communication, uncrewed vehicles, and vital sign recognizers. However, in the terahertz (THz) region, the development of RISs is limited because of lacking tunable phase shifters and low-cost sensors. Here, we developed an integrated self-adaptive metasurface (SAM) with THz wave detection and modulation capabilities based on the phase change material. By applying various coding sequences, the metasurface could deflect THz beams over an angle range of 42.8°. We established a software-defined sensing reaction system for intelligent THz wave manipulation. In the system, the SAM self-adaptively adjusted the THz beam deflection angle and stabilized the reflected power in response to the detected signal without human intervention, showing vast potential in eliminating coverage dead zones and other applications in THz communication. Our programmable controlled SAM creates a platform for intelligent electromagnetic information processing in the THz regime.

Spatial light modulators (SLM), capable of dynamically and spatially manipulating electromagnetic waves, have reshaped modern life in projection display and remote sensing. The progress of SLM will expedite next-generation communication and biomedical imaging in the terahertz (THz) range. However, most current THz SLMs are adapted from optical alternatives that still need improvement in terms of uniformity, speed, and bandwidth. Here, we designed, fabricated, and characterized an 8 × 8 THz SLM based on tunable liquid crystal metamaterial absorbers for THz single-pixel compressive imaging. We demonstrated dual-color compressive sensing (CS) imaging for dispersive objects utilizing the large frequency shift controlled by an external electric field. We developed auto-calibrated compressive sensing (ACS) algorithm to mitigate the impact of the spatially nonuniform THz incident beam and pixel modulation, which significantly improves the fidelity of reconstructed images. Furthermore, the complementary modulation at two absorption frequencies enables Hadamard masks with negative element values to be realized by frequency-switching, thereby halving the imaging time. The demonstrated imaging system paves a new route for THz single-pixel multispectral imaging with high reliability and low cost.

Dynamic manipulation of electromagnetic (EM) waves with multiple degrees of freedom plays an essential role in enhancing information processing. Currently, an enormous challenge is to realize directional terahertz (THz) holography. Recently, it was demonstrated that Janus metasurfaces could produce distinct responses to EM waves from two opposite incident directions, making multiplexed dynamic manipulation of THz waves possible. Herein, we show that thermally activated THz Janus metasurfaces integrating with phase change materials on the meta-atoms can produce asymmetric transmission with the designed phase delays. Such reconfigurable Janus metasurfaces can achieve asymmetric focusing of THz wave and directional THz holography with free-space image projections, and particularly the information can be manipulated via temperature and incident THz wave direction. This work not only offers a common strategy for realizing the reconfigurability of Janus metasurfaces, but also shows possible applications in THz optical information encryption, data storage, and smart windows.