Application of optical diffraction method in designing phase plates
Lei Ze-Min1, 2, Sun Xiao-Yan1, 2, Lv Feng-Nian1, Zhang Zhen1, Lu Xing-Qiang1, †,
       

Two-dimensional distributions of focal spots: (a) shaped by the CPP in Fig. 4, (b) shaped by the CPP in Fig. 5.