In this work, we report a tunable mode-locked fiber laser that can produce ultrashort laser pulses with polarization vortex. Two vortex wave plates (VWPs) are employed in this laser to convert the intracavity beam states between the Gaussian mode and cylindrical vector mode. By adjusting the angle between a diffraction grating and the light beam in the cavity, the center wavelength of the mode-locked pulse can be tuned from 1015 nm to 1030 nm. Mode-locked pulses with full width at half maximum of 1.51 ps with the maximum single pulse energy of 2.2 nJ have been obtained. Through synchronously adjusting the orientations of the two VWPs, the output mode can be switched between radial polarization and azimuthal polarization states. The output vortex pulse from the tunable mode-locked fiber laser may find many applications such as optical manipulation, imaging and laser micro-machining.

在这项工作中，我们报告了一种可调谐锁模光纤激光器，该激光器可以产生带有偏振涡的超短激光脉冲。在该激光器中使用两个涡旋波片（VWP）在高斯模式和圆柱矢量模式之间转换腔内光束状态。通过调节衍射光栅和腔中光束之间的角度，可以将锁模脉冲的中心波长从1015 nm调谐到1030 nm。已获得锁模脉冲，其半峰全宽为1.51 ps，最大单脉冲能量为2.2 nJ。通过同步调整两个VWP的方向，可以在径向极化和方位极化状态之间切换输出模式。可调谐锁模光纤激光器的输出涡旋脉冲可能会发现许多应用，例如光学操纵，