Valley Modes Separation of Chiral Landau Levels with In Plane Synthetic Gauge Fields in Gyromagnetic Photonic Crystals

Abstract The physical realization of the artificial magnetic field has been a fascinating field as it provides a new platform for manipulating waves. Compared to previous studies, the in‐plane synthetic gauge fields into the Haldane model is first introduced, and predict that the modes of chiral Landau levels (LLs) associated with K/K′ valleys will be separated in two strip bulks in real space. This unique phenomenon is further confirmed in simulations and experiments by constructing a microwave gradient gyromagnetic photonic crystals (PCs) immersed in a biased magnetic field (MF). It is found that the frequency and localized position of LLs can be modulated by changing the gradient. Further, the multifunctional optical devices, including frequency division multiplexers, valley converters and beam splitter, can be designed by coupling the LLs and edge states. These novel properties provide insights into the manipulation of electromagnetic waves and designing multifunctional optical devices in artificial microstructure.