Chinese Optics Letters, Vol. 16, Issue 8, 080501 (2018)
Generation of X-ray vortex with ultra-long depth of focus using axial line-focused spiral zone plates
Huaping Zang1,*, Chenglong Zheng1, Quanping Fan2, Chuanke Wang2, Lai Wei2,**, Leifeng Cao2, Xiangru Wang3, and Erjun Liang1
- 1School of Physics and Engineering, Zhengzhou University, Zhengzhou 450001, China
- 2Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China
- 3School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China
We propose axial line-focused spiral zone plates (ALFSZPs) for generating tightly focused X-ray vortex beams with ultra-long depth of focus (DOF) along the propagation direction. In this typical design, compared with the conventional spiral zone plates (SZPs) under the same numerical aperture (NA), the DOF of ALFSZPs has been extended to an ultra-length by optimizing the corresponding parameters. Besides, it also exhibits lower side lobes and smaller dark cores in the whole focus volume. The diameters of dark cores increase as the topological charge value increases.