Topological decomposition and transformation of photonic quasicrystals.

Photonic quasicrystals, generated through the interference of multiple vortex beams, exhibit rich and complex topological landscapes. However, unlike their periodic counterparts, they have far lacked the same level of controllability and reconfigurability. In this work, we develop a theoretical model to characterize the spin topology of photonic quasicrystals and uncover the intrinsic substructure underlying their quasi-periodic spin textures. By analyzing the formation mechanisms, we demonstrate the controlled decomposition and topological annihilation of individual sublattices within a quasicrystalline configuration. Based on this, we propose a phase-modulation method to reconfigure these topological states. We demonstrate that a quasicrystal with octagonal symmetry can be decomposed into two square meron lattices with a relative twist. This method is further extended to create more complex quasicrystals, where selective sublattice activation leads to meron bags. These findings provide new insights into both the static design and active manipulation of topological quasicrystals of light, paving the way for programmable topological photonic platforms with high spatial complexity and functional versatility.