Nonlocal metasurface based on the multiport structural model

Authors：Ren, Jie; Hou, Zhilin^*

Source：Physical Review Applied, 2023, 20(4): 044004.

DOI：10.1103/PhysRevApplied.20.044004

Recent progress on metasurfaces has revealed the nonlocal features of this kind of multiunit artificial structure. It has been shown that there is always intercoupling between the constituent units, which must be considered in their design. Such an intercoupling makes the design process difficult, especially when the number of constituent units becomes large. We show in this paper that a metasurface can be generally described by a multiport structural model, based on which an efficient design method can be established. To show the main idea of the model and the adaptability of the method based on it, nonlocal metastructures with various target fields, including an anomalous reflector, mode convertor in waveguide, wave focuser, and structure for a bound state in a continuum are designed. The successfully designed metastructures show that the suggested method is generally valid for structures with various target fields and is also efficient enough for structures with a large number of constituent units. The model gives not only an efficient method for designing metasurfaces, but also a general understanding of metastructures, based on which nonlocal metastructures for field control in complex environments, such as in organic tissue and architectural structures, can be expected.