Data from: Strong interlayer coupling and chiral flat-band cascades in twisted bilayer gratings

In few-layer van der Waals (vdW) materials, however, the intrinsically weak interlayer coupling typically demands fine control of small twist angles to reach magic-angle conditions. Here, we show that one-dimensional photonic crystal bilayers can overcome this limitation by accessing a regime of strong interlayer coupling—comparable to intralayer coupling.

This strong coupling enables flat-band formation over a broad angular range even at large twist angles. We experimentally realize this regime by stacking WS₂ gratings via a two-step lithography method, yielding ultra-wide chiral flat-band cascades in magic-angle twisted bilayer gratings. Our work not only provides a platform for designing photonic applications with a tunable localization but also explores a new regime of physics that is unattainable in conventional solid-state-based moiré systems.