Temporal Weyl physics and topological control of direction-selected radiation in anisotropic photonic time crystals
Phys. Rev. B 113, 205129 – Published 11 May, 2026
DOI: https://doi.org/10.1103/ttrs-5njx
Abstract
Anisotropic photonic time crystals (APTCs), enabled by periodic temporal modulation of a uniform anisotropic medium, exhibit asymmetric momentum-band gap structures and offer unique control over light–matter interactions. Here, we introduce and construct temporal Weyl points (TWPs) in APTCs within a synthetic three-dimensional space defined by two phase parameters and the quasifrequency. The temporal response reveals robust Fermi arcs linking TWPs of opposite topological charge. Unlike spatial counterparts, these Fermi arcs emerge only after the first temporal supercell comprising multiple periods of APTCs, reflecting causality. We further show that TWPs enable tunable emission from stationary charges embedded in APTCs, while the associated Fermi arcs robustly suppress radiation at selected directions and frequencies. Our findings establish temporal Weyl physics in photonic time crystals and uncover new opportunities for topological control of light–matter interactions through the time dimension.
