Gradient moiré perovskite superlattices for laser beam steering

Manipulation of laser emission characteristics plays a key role in diverse technologies. However, compact lasers with internal beam steering functionalities remain a challenge. Here, we demonstrate how gradient moiré perovskite superlattices can facilitate dynamic laser beam steering. By combining a two-dimensional (2D) square lattice with a globally curved 1D perovskite grating, we fabricated gradient moiré photonic superlattices with continuously variable twist angles. We revealed how the moiré interlayer coupling at the high-symmetry points on the Brillouin zone boundaries can produce additional cavity modes with twist angle-controlled wave vectors. We showed that the moiré-induced band-edge modes can support lasing with low thresholds. By sweeping the pump area to access different twist angles, we achieved tuning of laser emission angles in a continuous and wide range (>30°) from a single device. Our work provides a highly tunable platform for moiré-induced light-matter interactions, which opens prospects for programmable and intelligent photonic technologies.