Beam self-cleanup by use of self-written waveguide generated by photopolymerization.

A novel method for multimode fiber (MMF) laser-beam cleanup is introduced based on the optically induced growth and interaction of self-written waveguides (SWWs) in a photopolymer material. Theoretically, it is predicted that when the light is introduced into a free-radical photopolymerizable system from a MMF, the incident multichannel and structured beam shape can be caused to merge to form a single-channel Gaussian-like beam under specific exposure and material conditions. Experimental validation was carried out using a dry acrylamide/polyvinyl alcohol (AA/PVA) photopolymer sample. This work opens the door to studies involving self-developing laser beam cleanup and also to possible applications in photonic telecommunication systems and integrated optical devices.