Fig. 1. Transmittance for SZPs with the topological charge p=1 in (a) the (x, y) coordinate system and (b) the (r2, θ) coordinate system. Transmittance for ALFSZPs with the topological charge p=1 in (c) the (x, y) coordinate system and (d) the (r2, θ) coordinate system.

Fig. 2. Schematic diagram of diffraction by the ALFSZPs.

Fig. 3. (a) The calculated axial irradiance of conventional SZPs; (b) the calculated axial irradiance of ALFSZPs with focal depths from 450 to 550 mm, Δf=100  mm, N=699, and Δd=0.0858  μm2; (c) the calculated axial irradiance of ALFSZPs with focal depths from 475 to 525 mm, Δf=50  mm, N=699, and Δd=0.0429  μm2; (d) the calculated axial irradiance of ALFSZPs with focal depths from 475 to 525 mm, Δf=50  mm, N=349, and Δd=0.0858  μm2.

Fig. 4. (a), (b), and (c) Calculated diffraction patterns of ALFSZPs at the positions of 450, 500, and 550 mm. (d), (e), and (f) Calculated diffraction patters of conventional SZPs with the same parameters at the positions of 450, 500, and 550 mm.

Fig. 5. ALFSZPs with different integer topological charges and axial irradiances from 450 to 550 mm. (a), (b) The topological charge p=0. (c), (d) The topological charge p=1. (e), (f) The topological charge p=2.