We present a flexible, simple, and cost effective approach for generating high-quality multiple focal spots in the far field using composite spiral zone plates (SZPs), which serve as a synthesis of two SZPs with different topological charges. By changing the topological charges of the SZPs can obtain different types of multiple focal spots. The numerical solution, fabrication method, and experimental results are presented to prove the capabilities of this approach.
© 2012 Chinese Optics Letters
Diffraction and Gratings
Yilei Hua, Ziqiang Wang, Hailiang Li, Nan Gao, and Yuchan Du, "Multi-spot focusing by using composite spiral zone plates," Chin. Opt. Lett. 10, 120502-120502 (2012)