Feng Jie, Hu Kai-Xin, Cui Wen-Xue, Cao Ji, Wang Hong-Fu
Opt Express. 2025 Feb 24;33(4):7556-7568. doi: 10.1364/OE.551946.
We investigate the topological phase transition and localization properties in an array of optical cavities with periodic or quasiperiodic hopping. In both the commensurate and incommensurate regimes, the occurrence of the topological phase transition is confirmed by numerically calculating the real-space winding number. Moreover, due to the presence of quasiperiodicity, the system undergoes Anderson localization phase transition and exhibits topological Anderson insulators (TAIs) induced by quasiperiodic disorders in the incommensurate regime. Interestingly, unlike gapless and completely localized TAI in random disorder systems, we reveal gapped TAI with bulk states that have distinct localization properties, in addition to the gapless TAI with completely localized states. Furthermore, it is observed that the localized states in the band-center region will become delocalized and then localized again as the quasiperiodic parameter increases. Our findings provide insight into understanding the topology and localization properties of quasiperiodic optical systems.
我们研究了具有周期性或准周期性跳跃的光学腔阵列中的拓扑相变和局域化特性。在 commensurate 和 incommensurate 两种情况下，通过数值计算实空间缠绕数证实了拓扑相变的发生。此外，由于准周期性的存在，系统经历了安德森局域化相变，并在 incommensurate 情况下表现出由准周期性无序诱导的拓扑安德森绝缘体（TAIs）。有趣的是，与随机无序系统中的无隙和完全局域化的 TAI 不同，我们揭示了除了具有完全局域化态的无隙 TAI 之外，还存在具有不同局域化特性的体态的有隙 TAI。此外，观察到随着准周期参数的增加，带中心区域的局域态将先变得离域然后再次局域化。我们的研究结果为理解准周期光学系统的拓扑和局域化特性提供了见解。
