Fig. 1. Schematic diagram of two axicon types with spherical cone tip

Fig. 2. Eight kinds of axicon lens group arrangement diagram. (a)-(d) Double convex combination arrangement; (e)-(h) concave and convex combination arrangement

Fig. 3. Beam transformation diagram

Fig. 4. Diffraction pattern and cross-section normalized light intensity distribution diagram. (a) z₀=0 m; (b) z₀=10 m; (c) z₀=20 m; (d) z₀=30 m

Fig. 5. Variation curve of normalized light intensity of point on axis with transmission distance

Fig. 6. Variation curves of β with D/ω₀ under two kinds of encircled energy characterization

Fig. 7. Relationship between energy truncation loss and D/ω₀

Fig. 8. Variation of beam quality with ε under two kinds of encircle energy characterization. (a) 83.8% encircled energy; (b) 63.2% encircled energy

Fig. 9. Light path diagram of center and edge rays when cone-top angles are inconsistent

Fig. 10. Maximum optical path difference varying with deviation of cone-top angle

Fig. 11. Schematic diagram of axicon group when relative error exists. (a) Relative eccentricity; (b) relative tilt

Fig. 12. Variation curves of wavefront RMS with respect to relative error of conical mirror set at different cone-top angles. (a) Relative eccentricity; (b) relative tilt

Fig. 13. Beam far-field pattern. (a) Solid beam; (b) hollow beam

Fig. 14. Comparison of near and far field light spots before and after shaping. (a) Gaussian beam near field; (b) Gaussian beam far field; (c) hollow beam near field; (d) hollow beam far field