  Demonstrations of topological photonics have so far largely been confined to
infrared wavelengths where imaging technology and access to low-dimensional
quantum materials are both limited. Here, we designed and fabricated silicon
nitride ring-resonator arrays to demonstrate photonic topological edge states
at ~780 nm. We observed edge states corresponding to the integer quantum Hall
Hamiltonian with topological protection against fabrication disorder. This
demonstration extends the concept of topological edge states to the
near-visible regime and paves the way for nonlinear and non-Hermitian
topological photonics with the rich library of near-visible quantum emitters.
