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Abstract Recent progress has demonstrated that synthetic gauge fields can mimic Landau quantization in materials including graphene and lattices for sound and light. However, despite using graphene-like structures with strain-induced textures in prior photonics, it is hard to capture the experimental attainment of distinct photon bound states for various Landau levels. In this work, we introduce an experimental framework for achieving photonic Landau quantization. We present the quantized distribution of photonic states across different Landau levels in a two-dimensional Kagome metal lattice. By introducing inhomogeneous coupling, we implement two kinds of pseudomagnetic field, which quantize spectrums and quantizes distribution of photonic states, respectively. We experimentally observe that the electric field distribution is localized according to the positional attributes of different Landau levels. Our proposed system is more straightforward to implement, and it opens an avenue to explore photonic states at non-zero Landau levels, which are predicted to demonstrate some interesting physical phenomena.

Abstract In photonic crystal systems, topologically protected edge states and corner states can be achieved by breaking spatial inversion symmetry, which is expected to be applied to topologically protected lasers, optical communication and integrated photonics. However, designing ultrabroadband topological photonic crystals is still a challenge. In this work, we propose a valley photonic crystal composed of dendritic structures, which can realize valley transmission with a relative bandwidth up to 59.65%. Compared with the previously reported two-dimensional broadband photonic crystals with 32.02% bandwidth, the relative bandwidth of the proposed valley transmission is increased by almost 100%. Theoretical analysis, numerical simulation and experimental measurement all confirm flexible manipulation of electromagnetic wave propagation paths. Ultrabroadband topological waveguides with the zigzag and armchair interface are demonstrated, which can achieve experimentally 58.71% and 36.78% relative bandwidth, respectively. In addition, several topological channel intersections are designed. Finally, two types of corner states with valley switchability and selectivity are demonstrated.