Fig. 1: Conceptual comparison between structural and temporal approaches to polarization control.
From: All-optical polarization control in time-varying low-index films via plasma symmetry breaking
Top: structural metasurfaces employ geometrically distinct designs to achieve reciprocal (R) birefringence, dichroism or chirality, each requiring separate fabrication. Bottom: in contrast, temporal materials respond to tailored optical excitations, where the time profile and polarization of the incident beam dynamically induce birefringent, dichroic or chiral behaviours in a single unpatterned substrate. This temporal engineering approach greatly enhances reconfigurability, reduces fabrication overhead and expands the accessible optical response space while also enabling non-reciprocal functionalities.
