Quantized Hall Drift in a Frequency-Encoded Photonic Chern Insulator

Chern insulators are topological phase of matter with broken time-reversal symmetry <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathscr{T})$</tex>. One of the most famous realization of such a phase is provided by the quantum Hall effect, describing a two-dimensional electron gas submitted to a strong external magnetic field. Thanks to the underlying topology of the electronic states, these materials exhibit universal quantized plateaus in their transverse conductivity that are notoriously robust to local perturbations and environmental noise, making them valuable for numerous applications in metrology and quantum technologies. However, implementing photonic analogues of topological materials with broken <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathscr{T}$</tex> (akin to the quantum Hall effect) has proven to be technically challenging, mainly due to the weak magneto-optical response of matter at optical or near infrared frequencies.