We demonstrate a photonic analog of twisted bilayer graphene that has ultra-flat photonic bands and exhibits extreme slow-light behavior. Our twisted bilayer photonic device, which has an operating wavelength in the C-band of the telecom window, uses two crystalline silicon photonic crystal slabs separated by a methyl methacrylate tunneling layer. We numerically determine the magic angle using a finite-element method and the corresponding photonic band structure, which exhibits a flat band over the entire Brillouin zone. This flat band causes the group velocity to approach zero and introduces light localization, which enhances the electromagnetic field at the expense of bandwidth. Using our original plane-wave continuum model, we find that the photonic system has a larger band asymmetry. The band structure can easily be engineered by adjusting the device geometry, giving significant freedom in the design of devices. Our work provides a fundamental understanding of the photonic properties of twisted bilayer photonic crystals and opens the door to the nanoscale-based enhancement of nonlinear effects.

我们展示了一种扭曲双层石墨烯的光子模拟物，它具有超平坦的光子带并表现出极端的慢光行为。我们的扭曲双层光子器件的工作波长在电信窗口的 C 波段，它使用两个由甲基丙烯酸甲酯隧道层隔开的晶体硅光子晶体板。我们使用有限元方法和相应的光子能带结构以数值方式确定魔角，该光子能带结构在整个布里渊区显示出平坦带。该平坦带导致群速度接近零并引入光定位，这以带宽为代价增强了电磁场。使用我们最初的平面波连续介质模型，我们发现光子系统具有更大的带不对称性。可以通过调整器件几何形状轻松设计能带结构，从而为器件设计提供极大的自由度。我们的工作提供了对扭曲双层光子晶体的光子特性的基本理解，并为基于纳米级的非线性效应增强打开了大门。