The zero refractive index properties of two-dimensional photonic crystals(PCs) are studied theoretically. Three necessary conditions for PCs to mimic the zero index materials(ZIMs) are obtained. In addition, through a...The zero refractive index properties of two-dimensional photonic crystals(PCs) are studied theoretically. Three necessary conditions for PCs to mimic the zero index materials(ZIMs) are obtained. In addition, through a comparative study of the properties for two representative PC structures with different types of Dirac cones, we find that the PC with a Dirac-like cone which meets the three necessary conditions does not behave as a ZIM in some cases. Further analysis shows that its non-zero index properties originate from the flat dispersion band.These findings clarify the fundamental physical issue of which type of Dirac cone PC can mimic a real ZIM.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11504336 and 61805214the Fundamental Research Funds for the Central Universities under Grant No 265201430
文摘The zero refractive index properties of two-dimensional photonic crystals(PCs) are studied theoretically. Three necessary conditions for PCs to mimic the zero index materials(ZIMs) are obtained. In addition, through a comparative study of the properties for two representative PC structures with different types of Dirac cones, we find that the PC with a Dirac-like cone which meets the three necessary conditions does not behave as a ZIM in some cases. Further analysis shows that its non-zero index properties originate from the flat dispersion band.These findings clarify the fundamental physical issue of which type of Dirac cone PC can mimic a real ZIM.
