高斯光束经过负球差透镜的聚焦

Focusing Gaussian beams by lenses with negative spherical aberration

本文讨论高斯光束经过负球差透镜的聚焦，得到了聚焦光场轴上点的光强分布的表示式，并对其进行数值计算。数值计算结果表明，在负球差的情况下，得到光强的最大点位置（最佳聚焦点）相对于无球差情况，往透镜方向移动，并且，最佳聚焦点的光强较无球差时大，当Ｎｗ＝１，Ｎａ＝５，ｋＳ１＝－０．２时，得到的最佳聚焦点的光强是无球差时的１．３４倍。本文还讨论了透镜的菲涅尔数对聚焦光场分布的影响。结果表明，当透镜的菲涅尔数小于１时，球差对高斯光束的聚焦的影响可以忽略。

In this paper, focusing of Gaussian beams by lenses with negative spherical aberration is discussed. The expressions for the axial light intensity of Gaussian beams focused by a lens with primary spherical aberration have been derived. The numerial calculation shows that the best focal position will shift towards the lens, and larger axial maximum light intensity can be achieved comparising with the case of no spherical aberration. When Nw=1,Na=5,kS1=-02, the axial maximum light intensity is the 134 times of that in the case of no aberration. The effect of the Fresnel number of the lens on the axial focused light distribution is also discussed. It is shown that then the Fresnel number of the aberrated lens is smaller than 1, the effect of the spherical aberration on the focusing Gaussian beams can be neglected.