No abstract

We report a q-plate-waveguide hybrid optical vortex emitter processed by femtosecond laser directly writing the lithium niobate (LN) single crystal. Both simulation and experimental results show that by utilizing the geometric phase of the q-plate, the fabricated device can convert the incident Gaussian beam into the vortex beam with orbital angular momentum (OAM) and realize the low-loss transmission of the vortex beam in the double-cladding waveguide. Our results demonstrate that the q-plate-waveguide hybrid structure has great prospects promoting the development of photonic integrated chips (PICs) with generating and propagating a vortex beam with a certain topological charge.