Metamaterials (MMs) and photonic crystals (PhCs) exhibiting artificially engineered physical properties have been widely studied in the past decade. However, abnormal properties could only be proposed under a limited range of polarization and directions in most of the previous studies. It is still a challenge to realize an isotropic artificial material with multiple exotic electromagnetic properties. Here we report a three-dimensional metacrystal supporting full polarization and omni-directional incidence. The center-symmetric unit cell consists of non-resonant closed metallic loops on each surface of the dielectric cube. With the cross-scale dispersion engineering, the metacrystal can exhibit an isotropic diamagnetic response and an all-angle negative index of refraction simultaneously at the opposite sides of the MM-PhC transition region. An additional numerical analysis shows the good performance in terahertz and mid-infrared frequencies, which indicates its potential applications on multi-functional optical components with wide polarization-and-direction allowance.

中文翻译：

---

具有宽带各向同性反磁响应和全角度负折射率的三维超晶

在过去的十年中，已经广泛研究了具有人工工程物理特性的超材料（MMs）和光子晶体（PhCs）。但是，在大多数先前的研究中，只能在有限的极化和方向范围内提出异常特性。实现具有多种异乎寻常的电磁特性的各向同性人造材料仍然是一个挑战。在这里，我们报告了支持全极化和全向入射的三维超晶体。中心对称的单元电池由介电立方体每个表面上的非谐振闭合金属环组成。通过跨尺度色散工程，该准晶可以在MM-PhC过渡区域的相对两侧同时显示出各向同性的反磁响应和全角度负折射率。