Band structure and topological phase transition of photonic time crystals

作者：Ji Ma, Zhiguo Wang · 发表于：Optics Express · 年份：2019 · DOI：10.1364/oe.27.012914 · 被引用次数：17 · 研究领域：Topological Materials and Phenomena、Photonic Crystals and Applications、Neural Networks and Reservoir Computing

We investigate the band structure and topological phase transition of photonic time crystals (PTC)-systems in which the physical parameter varies periodically in time. We find that the topological phase transition of the PTC system can be revealed by the wave vector gap (k-gap) size, which was induced by the temporal refraction and reflection. Interestingly, a temporal zero-averaged refractive index k-gap is obtained when the PTC system includes a dispersive medium. This special k-gap is invariant with modulation time scaling at a given modulation frequency.