1.7 μm sub-200 fs vortex beams generation from a thulium-doped all-fiber laser

The pulsed 1.7 mu m vortex beams (VBs) has significant research prospects in the fields of imaging and material processing. We experimentally demonstrate the generation of sub-200 fs pulsed VBs at 1.7 mu m based on a home-made mode-selective coupler (MSC). Through dispersion management technology in a thulium-doped fiber laser, the stable linearly polarized VBs pulse directly emitting from the cavity is measured to be 186 fs with central wavelength of 1721.2 nm. By controlling the linear superposition of LP11 modes, cylindrical vector beams (CVBs) can also be obtained. In addition, a variety of bound states pulsed VBs at 1.7 mu m can also be observed. Our finding provides an effective way to generate ultrashort pulsed VBs and CVBs at 1.7 mu m waveband. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

The generation of sub-200 fs pulsed vortex beams (VBs) at 1.7 μm was successfully achieved through a homemade mode-selective coupler, and cylindrical vector beams (CVBs) can also be obtained by controlling the linear superposition.