Flexible Diffraction Control Terahertz Metagrating in Multiple Degrees of Freedom With High Efficiency

ABSTRACT Flexibly tunable metadevices have attracted considerable attention due to their capability for real‐time beam manipulation, which is regarded as a key technology for advancing next‐generation photonic devices. However, designing efficient and flexibly tunable metadevices in the terahertz region remains a long‐term challenge. Traditional gradient‐phase metasurfaces rely on discrete phase mapping, suffering from relatively low diffraction efficiency. Here, we demonstrate a design strategy based on metagratings for flexible control of terahertz waves. Tailoring the structural parameters of the metagratings precisely, flexible control of the energy distribution between the diffractive orders is achieved, resulting in desirable manipulation and diffraction efficiency. The metagratings are fabricated by photocuring 3D printing technology. The measured highest manipulation efficiency and transmission efficiency are 95.4% and 92.6%, respectively. By changing the incident angle of terahertz waves, terahertz beam steering in the radiation field is experimentally validated with a steering range of 80°. Besides, flexible spectral tuning is realized, with a maximum frequency shift of transmission peaks of 90 GHz. The presented concept is universal and enriches the functionalities of metagratings, making it promising for applications in radar, remote sensing, multispectral cameras, and super‐resolution imaging. With advanced fabrication processing technology, this approach facilitates the development of multifunctional next‐generation metadevices.