It is well known that a photonic crystal composed of metal rods in a dielectric background exhibits a cutoff frequency below which the propagation of light is forbidden. The cutoff frequency usually increases as the volume fraction of the metal rod increases. However, we report that the cutoff frequency of a photonic crystal composed of metal rods and an epsilon-near-zero material background is independent of the volume fraction and identical to the plasma frequency of the metal rod. The extremely long wavelength of light in an epsilon-near-zero material causes this interesting phenomenon.

中文翻译：

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由金属棒和ε接近零的材料组成的二维光子晶体的恒定截止频率

众所周知，由介电背景中的金属棒组成的光子晶体具有截止频率，在该截止频率以下，光的传播被禁止。截止频率通常随着金属棒体积分数的增加而增加。但是，我们报告说，由金属棒和epsilon-near-zero材料背景组成的光子晶体的截止频率与体积分数无关，并且与金属棒的等离子体频率相同。ε接近零的材料中极长的光波长会引起这种有趣的现象。