Propagation of Flattened Beams Through an Astigmatic Lens and Changes in Their Beam Parameters
平顶光束通过像散透镜的传输和光束参量的变化

The propagation of flattened beams through an astigmatic lens and changes in their beam parameters,such as the beam width,waist width and position,far-field divergence angle and M2 factor were studied.It is found that the astigmatism gives rise to an increase of the waist width and a decrease of the far-field divergence angle in the x direction,and the real focal position shifts far away from the lens.The results in the y direction are in contrary.The M2 factor of flattened beams is independent of the astigmatism.The relative errors of the beam width and far-field divergence angle vary with the beam order,astigmatic coefficient,Raleigh length and focal length of the lens.The relative errors of the beam width in the x and y directions at the geometric focal plane are equal if the beam orders in the two directions and initial beam width are equal,whereas they are different at the real focal plane.