Artificial gauge fields for sculpting topological modes on photonic chips.

Topological states, which often manifest as localized modes at interfaces between distinct topological phases, and their manipulation have attracted considerable interest in research. Here, we demonstrate a versatile approach to sculpting topological modes into desired shapes by incorporating various artificial gauge fields -including scalar, vector, and imaginary gauge potentials-and leveraging the power of artificial neural networks. The chose gauge fields enable precise tuning of the dissipation of the topological modes across that of bulk modes, facilitating a transition from localized states to fully delocalized ones. These eigen modes can be precisely engineered by neural networks, achieving tailored profiles of topological states, which remain spectrally isolated from bulk bands and exhibit minimal loss compared to other modes. Our theoretical results are experimentally validated on silicon photonic platforms, demonstrating flexible manipulation of mode profiles. This approach enables the design of topological states with customized properties, offering potential for diverse applications in photonics and beyond.