https://doi.org/10.1140/epjp/s13360-024-05902-9
Regular Article
Tunable THz co-coding beam splitting metasurfaces based on superconducting NbN and gold materials
College of Information Science and Technology, Nanjing Forestry University, 210037, Nanjing, China
Received:
5
July
2024
Accepted:
4
December
2024
Published online:
30
December
2024
The tunable multi-beam has important roles in real-time detection, environmental sensing and so on. We demonstrate in this paper the tunable terahertz (THz) digital coding beam-splitting metasurfaces based on superconducting niobium nitride (NbN) and Gold materials. Based on the amplitude modulation (AM) mode of NbN, co-coding of phases and materials for tunable beam-splitting metasurfaces are proposed, including Regional Independent Modulation (RIM) and NbN + Gold Composite Modulation (CM). The variation of splitting beam number and ratio with temperature from the superconducting state to normal state is theoretically realized. The advantage of RIM can individually tune the intensity of certain beams without affecting others. Comparatively, CM design is more flexible, and different co-coding sequences can achieve diversity for far-field beams. To further increase the number of tunable beams, based on the 1-bit CM metasurfaces, the extension of 1D into 2D space by co-coding addition is discussed. As a verification of the theoretical method, tunable beam-splitting metasurfaces with main beams number ranging from 4 to 2, 2 to 3, and 16 to 8 at 0.85 THz are realized. The method proposed in this paper provides an effective approach for the design of amplitude tunable devices and NbN-based beam modulated metasurfaces.
Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjp/s13360-024-05902-9.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
