Fig. 1. Diffraction system. (a) Optical path diagram of the diffraction system; (b) radial cosine grating

Fig. 2. Diagrams of radial cosine gratings with different numbers of spokes and the light intensity distribution of diffraction-free petal beams with reticulated optical lattices produced by radially polarized beams passing through the corresponding diffraction system. (a)(e) m=0; (b)(f) m=5; (c)(g) m=10; (d)(h) m=20

Fig. 3. Light intensity distribution of diffraction-free petal beams. (a) Light intensity distribution on ρ-z plane; (b) three-dimensional light intensity distribution; (c) normalized light intensity cross section within range 200‒600 mm; (d) normalized light intensity cross section within range 800‒1000 mm

Fig. 4. Schematic diagram of an axicon with hyperbolic vertices

Fig. 5. Intensity distribution of radially polarized beam with different waist radius by a radial cosine grating and then through an ideal axicon and a hyperbolic vertex axicon. (a)‒(d) ω=1mm; (e)‒(h) ω=2mm; (i)‒(l) ω=3mm; (m)‒(p) ω=5mm