Optical fabrication of (2 + 1)-dimensional photorefractive photonic lattices by improved Billet split lens

A convenient way to optical fabricate (2 + 1)-dimensional photonic lattice microstructures was experimentally demonstrated in photorefractive crystal. An improved Billet split lens combined with a Fourier transform lens can generate large area interference of multiple plane waves. The (2 + 1)-dimensional square photonic lattice microstructures are optically induced in an iron doped lithium niobate crystal. Induced lattice microstructures are analyzed and validated using several different experimental methods. This method has good flexibility and scalability, stable equipment, and does not require complex adjustment systems. It can be used to optical fabricate more types of (2 + 1)-dimensional lattice microstructures by design and processing of improved Billet split lens reasonably.