Fig. 1. Phase structure of two-dimensional binary grating

Fig. 2. Phase difference of diffraction under two-dimensional Nyquist grating

Fig. 3. Complex amplitude distributions of Bessel vortex beams with topological charges of 5, 50, and 100 and their encoded holograms. (a) Intensity distribution maps; (b) phase distribution diagrams; (c) checkerboard grating holograms with a pixel period

Fig. 4. Experimental device for generating Bessel beams by checkerboard phase lattice method

Fig. 5. Intensity distributions of Bessel vortex beam prepared by experiment under different topological charges

Fig. 6. Intensity distributions of Bessel vortex beams at first-order modulation and zeroth-order modulation under different l_a values. (a) Bessel vortex beam at l_a=2; (b) Bessel vortex beam at l_a=8; (c) Bessel vortex beam at l_a=100

Fig. 7. Variation curves of zeroth-order and first-order mode purity of Bessel vortex beam when topological charge is 10--100

Fig. 8. Diffraction efficiency of Bessel vortex beams prepared at zeroth-order and first-order diffraction when topological charge is 10--100