球差透镜对余弦高斯光束聚焦特性的影响

本文基于余弦高斯光束通过球差透镜聚焦的轴上光强分布表达式,讨论了球差系数kS1及高斯光束菲涅耳数Nw对轴上光强的影响。数值计算结果表明负球差可作为获得轴向光强平顶分布的一种方法。当无球差时,最佳聚焦点位于几何焦点的左侧。当透镜具有正球差时,通过改变菲涅耳数Nw可以实现最佳聚焦点由几何焦点左侧zf1快速跃变到右侧zf2,此时出现焦开关现象。球差系数越大,对应的相对跃迁量Δzf=|zf1-zf2|也越大,而临界菲涅耳数(Nw)c则越小,如当kS1=0.5和0.3时,发生跃变的临界点分别为(Nw)0.5=7.03和(Nw)0.3=8.68,其相对跃迁量Δzf分别为0.246及0.146。

Energies and Transition Rates of Low-Lying Excited States for Beryllium

Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also calculated. Our results are in good agreement with other theoretical data.