Metamaterials with a Dirac-like cone dispersion at the center of the Brillouin zone behave like an isotropic and impedance-matched zero refractive index material at the Dirac-point frequency. Such metamaterials can be realized in the form of either bulk metamaterials with efficient coupling to free-space light or on-chip metamaterials that are efficiently coupled to integrated photonic circuits. These materials enable the interactions of a spatially uniform electromagnetic mode with matter over a large area in arbitrary shapes. This unique optical property paves the way for many applications, including arbitrarily shaped high-transmission waveguides, nonlinear enhancement, and phase mismatch-free nonlinear signal generation, and collective emission of many emitters. This review summarizes the Dirac-like cone-based zero-index metamaterials’ fundamental physics, design, experimental realizations, and potential applications.

在布里渊区中心具有类似狄拉克色散的超材料在狄拉克点频率下表现得像一种各向同性且阻抗匹配的零折射率材料。这种超材料可以以与自由空间光有效耦合的块状超材料或与集成光子电路有效耦合的片上超材料的形式实现。这些材料使空间均匀的电磁模式与任意形状的大面积物质相互作用成为可能。这种独特的光学特性为许多应用铺平了道路，包括任意形状的高传输波导、非线性增强和无相位失配的非线性信号生成，以及许多发射器的集体发射。