高斯光束通过环状球差透镜后的光束质量

以桶中功率(PIB)及β值为光束质量评价参数,分析了环状球差透镜的遮拦比、球差系数等参数对高斯光束光束质量的影响。值得指出的是:(1)由于焦移,在实际焦面比几何焦面上可得到更大的PIB;(2)适当选用负球差环状透镜可实现β1,于是可获得比通过无球差环状透镜更高的能量集中度。

Beam quality of Gaussian beams passing through a spherically aberrated annular lens

With power in the bucket(PIB) and β parameter to characterize beam quality,the effect of some parameters,such as spherical aberration coefficient C 4 and obscure ratio ε,on the beam quality of Gaussian beams is analyzed.It is worthwhile to note that PIB is larger at the actual focal plane than that at the geometrical plane due to focal shift,and that β can become less than 1 when a negative spherically aberrated annular lens is properly selected,hence a higher energy density beam can be achieved compared with the case of the annular lens without spherical aberration.