Necklacelike solitons in optically induced photonic lattices

We report the first observation of stationary necklace-like solitons. Such necklace structures were realized when a high-order vortex beam was launched appropriately into a two-dimensional optically induced photonic lattice. Our theoretical results obtained with continuous and discrete models show that the necklace solitons resulting from a charge-4 vortex have a pi phase difference between adjacent pearls and are formed in an octagon shape. Their stability region is identified.