Effect of relative lattice intensity of Lieb lattice on the propagation of out-of-phase octupole beam

In the present study, a new Lieb lattice with five points(hereinafter referred to as Lieb-5 lattice) in the minimum periodic unit is used as a platform. The sites of Lieb-5 lattices are classified into two categories according to their spatial position, respectively, the center lattice and the edge lattices. We investigate the effect of two categories lattices with different intensity on the propagation of the out-of-phase octupole beam. According to simulation results, when the intensity of the center lattice is less than that of the edge lattices(the ratio of two lattice intensities is 2:3), eight-peak shape is always maintained during beam propagation, presenting “strong localization”. Otherwise, the energy between incident lattices is periodically coupled with the increase of propagation distance, presenting “weak localization.”