Optical soliton formation controlled by angle twisting in photonic moire lattices

Moire lattices optically induced in photorefractive nonlinear media are used to explain the formation of optical solitons under different geometrical conditions controlled by the twisting angle between the constitutive sublattices. Exploration of the impact of synthetic material landscapes featuring tunable geometrical properties on physical processes is a research direction that is currently of great interest because of the outstanding phenomena that are continually being uncovered. Twistronics and the properties of wave excitations in moire lattices are salient examples. Moire patterns bridge the gap between aperiodic structures and perfect crystals, thus opening the door to the exploration of effects accompanying the transition from commensurate to incommensurate phases. Moire patterns have revealed profound effects in graphene-based systems(1-5), they are used to manipulate ultracold atoms(6,7)and to create gauge potentials(8), and are observed in colloidal clusters(9). Recently, it was shown that photonic moire lattices enable observation of the two-dimensional localization-to-delocalization transition of light in purely linear systems(10,11). Here, we employ moire lattices optically induced in photorefractive nonlinear media(12-14)to elucidate the formation of optical solitons under different geometrical conditions controlled by the twisting angle between the constitutive sublattices. We observe the formation of solitons in lattices that smoothly transition from fully periodic geometries to aperiodic ones, with threshold properties that are a pristine direct manifestation of flat-band physics(11).