Fig. 1. Structure and phase modulation characteristics of binary phase plate. (a) Structure of binary phase plate; (b) phase modulation characteristics of one-dimensional period

Fig. 2. Spectrum distribution and phase value of binary phase plate. (a) Normalized spectrum intensity distribution of binary phase plate; (b) normalized intensity distribution of the filtered spectrum; (c) relationship between (φ2-φ1) and b/a

Fig. 3. Phase distribution of first-order spectrum spots

Fig. 4. Simulation results of square beam array. (a) Normalized intensity distribution of square beam array; (b) phase distribution of square beam array

Fig. 5. Phase distribution of the second-order spectrum spots

Fig. 6. Simulation results of square optical vortex array. (a) Normalized intensity distribution of square optical vortex array; (b) phase distribution of square optical vortex array

Fig. 7. Curve of amplitude ratio U1/U2 between square beam array and square optical vortex array with phase plate parameter b/a

Fig. 8. Amplitude comparison between square beam array and square optical vortex array

Fig. 9. Simulation results of square optical helix array. (a) Normalized intensity distribution of square optical helix array; (b) phase distribution of square optical helix array

Fig. 10. Propagation of square optical helix array. (a) Three-dimensional diagram of propagation of square optical helix array; (b) normalized intensity distribution of square optical helix array at different propagation distances

Fig. 11. Optical system diagram

Fig. 12. Experimental results. (a) Intensity distribution of square beam array; (b) intensity distribution of square optical vortex array; (c) intensity distribution of square optical helix array at different propagation distances