General structured light generation based on programmable linearly-polarized mode synthesizer

Abstract

Fiber-based structured light including cylindrical vector beams (CVBs) and orbital angular momentum (OAM) has gained significant interest in various areas of study for the unique properties of spatial intensity, phase, and polarization distributions. Different approaches have been proposed for the generation of these spatially structured beams such as beam reshaping or directly lasing from specific cavities. In this work, we propose the concept of programmable linearly-polarized (LP) -mode Synthesizer for general structured light generation, in which an LP-mode Pool supporting independent and selectable LP-mode output is first established, and then different CVB/OAM modes could be generated in general way through polarization and phase control according to their conversion relation with LP modes. We demonstrate a proof-of-concept LP-mode Synthesizer based on a fiber ring laser characterized by partial 5-LP mode weakly-coupled few-mode fiber (FMF) cavity and arbitrary LP-mode switch array. Various CVB/OAM beams including TE₀₁, TM₀₁, OAM₊₁, OAM_-1, OAM₊₂, and OAM_-2 modes are successfully generated. This approach provides new insights into mode manipulation methods and could enhance the performance of various structured light applications such as optical and quantum communications, optical fiber sensing, microscopy, and optical trapping.