Impedance-matched metadevices with a single matrix material

Abstract Artificial periodic structures including photonic crystals (PCs) and metamaterials have been widely employed to construct metadevices, whereas their effective refractive indices n e and relative impedances Z r are usually coupled together and hard to design separately. Here, we present a me...

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Bibliographic Details
Main Authors: Yichen Li, Xiaodong Sun, Heming Shen, Xinhua Hu
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-025-01559-1
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Summary:Abstract Artificial periodic structures including photonic crystals (PCs) and metamaterials have been widely employed to construct metadevices, whereas their effective refractive indices n e and relative impedances Z r are usually coupled together and hard to design separately. Here, we present a method for flexibly tuning the indices n e and impedances Z r of PCs. The unit cell of PC consists of a dielectric matrix with multiple air holes symmetrically distributed around the center of the unit cell. We find that the index n e of the PC mainly depends on the filling ratio of the dielectric, while its impedance Z r relies on the position of the holes. When the holes have an appropriate distance from the center of the unit cell, matched impedances (Z r = 1) can be achieved for PCs with different indices n e . As a result, impedance-matched metadevices, such as generalized Mikaelian lenses with high efficiency (> 96%), can be constructed even with high refractive indices in their matrices.
ISSN:2045-2322