Asynchronous Space‐Time‐Coding Digital Metasurface. Issue 24 (25th June 2022)

• Record Type: Journal Article
• Authors: Wang, Si Ran; Chen, Ming Zheng; Ke, Jun Chen; Cheng, Qiang; Cui, Tie Jun
• Is Part Of: Advanced science. Volume 9:Issue 24(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-25
• Subjects: asynchronous -- automatic spatial scanning of the harmonics -- dynamic generation of radar cross sections -- frequency discontinuities -- space‐time‐coding digital metasurfaces; Science -- Periodicals; 505
• DOI: 10.1002/advs.202200106
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: Recent progress in space‐time‐coding digital metasurface (STCM) manifests itself a powerful tool to engineer the properties of electromagnetic (EM) waves in both space and time domains, and greatly expands its capabilities from the physical manipulation to information processing. However, the current studies on STCM are focused under the synchrony frame, namely, all meta‐atoms follow the same variation frequency. Here, an asynchronous STCM is proposed, where the meta‐atoms are modulated by different time‐coding periods. In the proposed asynchronous STCM, the phase discontinuities on traditional metasurface are replaced with the frequency discontinuities. It is shown that dynamic wavefronts can be automatically realized for both fundamental and high‐order harmonics by elaborately arranging the spatial distribution of meta‐atoms with various time‐coding periods. The physics insight is due to the accumulated rapidly changing phase difference with time, which offers an additional degree of freedom during the wave‐matter interactions. As a proof‐of‐principle example, an asynchronous STCM for automatic spatial scanning and dynamic scattering control is investigated. From the theory, numerical simulations, and experiments, it can be found that the proposed STCM exhibits significant potentials for applications in radars and wireless communications. Abstract : An asynchronous space‐time‐coding digital metasurface (ASTCM) is proposed to generate dynamic wavefronts by modulating the meta‐atoms with various periods. It is the first time to introduce frequency discontinuities to the digital coding metasurfaces. The outstanding abilities of the ASTCM include the automatic spatial scanning and dynamic scattering control, thus benefiting its applications in radars and wireless communications.