Non-Abelian Gauge Field Optics in the Time Domain

Artificial gauge fields open up burgeoning opportunities for wave engineering in different disciplines. So far, previous works have mostly focused on synthesizing spatial gauge fields, where the pseudomagnetic fields lie at the heart of these phenomena. In this Letter, we generalize the paradigm of gauge field optics to the time domain by using time-varying media with rotating anisotropy. Dual to its spatial counterpart, the temporal gauge field induces a pseudoelectric field for optical pulses, leading to the spin-dependent longitudinal shift and Zitterbewegung for both trajectory and frequency. In addition, we analyze the temporal non-Abelian interference effect induced by temporally bounded non-Abelian gauge field media, which results in the temporal spin-precession and the temporal analogy of the non-Abelian Aharonov-Bohm effect. Our Letter not only fills the gap between synthetic gauge fields and time-varying physical systems, but also provides a fundamentally new approach for manipulating light with time-varying media.