Fig. 1. Diagram of an axicon illuminated by an oblique vortex beams

Fig. 2. Relationship between C(h) and h under different deflection angles

Fig. 3. Numerical simulation for diffraction pattern under different deflection angles at a distance of z=500 mm

Fig. 4. Numerical simulation for diffraction pattern of divided dark cores. (a) m=2, η=5°; (b) m=3, η=7°; (c) m=4, η=8°; (d) m=5, η=9°

Fig. 5. Line chart of topological charge and appropriate deflection angle at a distance of z=500 mm

Fig. 6. Numerical simulation for diffraction pattern of divided dark cores at different distances (m=4, η=9°).(a) z=250 mm; (b) z=300 mm; (c) z=350 mm; (d) z=400 mm; (e) z=450 mm

Fig. 7. Experimental setup

Fig. 8. Experimental diffraction patterns under different deflection angles

Fig. 9. Experimental diffraction patterns of divided dark cores. (a) m=2, η=5°; (b) m=3, η=7°; (c) m=4, η=8°; (d) m=5, η=9°

Fig. 10. Experimental diffraction patterns of divided dark cores at different distances (m=4, η=9°). (a) z=250 mm; (b) z=300 mm; (c) z=350 mm; (d) z=400 mm; (e) z=450 mm