Fig. 1. ESRP gratings with different q values with γ = π/2. (a) q = 3; (b) q = 4; (c) q = 5; (d) q = 6; (e) q = 7; (f) q = 8.

Fig. 2. Simulated patterns of diffraction intensity at different propagation distances. (a) z = 60 cm; (b) z = 80 cm; (c) z = 100 cm. First row: shape-invariant lattice. Second row: propagation-invariant lattice.

Fig. 3. Phase and intensity diagrams of the x–z plane for q = 7 and γ = π/2. (a) Sectional intensity pattern; (b) sectional phase pattern.

Fig. 4. Simulated patterns of diffraction intensity from radial PGs at different values of γ. (a) γ = π/2; (b) γ = 2.40; (c) γ = π; (d) γ = 3π/2; (e) γ = 5.52; (f): γ = 2π. First row: shape-invariant lattice. Second row: propagation-invariant lattice.

Fig. 5. Simulated patterns of diffraction intensity from radial PGs at different numbers of spokes q. (a) q = 3; (b) q = 4; (c) q = 5; (d) q = 6; (e) q = 7; (f) q = 8. First row: intensity patterns. Second row: phase patterns.

Fig. 6. Experimental setup for generating the radial lattice.

Fig. 7. Experimental diffraction intensity patterns at different propagation distances. (a) z = 60 cm; (b) z = 80 cm; (c) z = 100 cm. First row: shape-invariant lattice. Second row: propagation-invariant lattice.

Fig. 8. Experimental patterns of diffraction intensity from radial PGs with γ = π/2 at different numbers of spokes q. (a) q = 3; (b) q = 4; (c) q = 5; (d) q = 6; (e) q = 7; (f) q = 8.