All-Fiber Laser With Intracavity Acousto-Optic Dynamic Mode Converter for Efficient Generation of Radially Polarized Cylindrical Vector Beams

We report an all-fiber laser that emits a radially polarized cylindrical vector beam (CVB) at 1 μm based on an intracavity acousto-optic mode converter. We efficiently generate the CVB, taking advantage of the acousto-optic coupling from the HE
₁₁
mode to the TM
₀₁
mode in a two-mode fiber. The laser can be switched from emitting a Gaussian-like beam to a radially polarized CVB. Radially polarized CVBs with modal and polarization purities >98% and a maximum power of 65 mW were generated.