Fig. 1. Schematic of the fabrication of geometric phase optical element based on nanograting

Fig. 2. Nanograting structure induced by femtosecond laser. (a) Schematic of the femtosecond laser processing system; (b) SEM image of the nanograting

Fig. 3. SEM images of nanograting induced by different laser polarization directions

Fig. 4. Effect of different pulse densities on phase retardance of nanograting when the processing depth is 200 μm and the pulse energy is 0.3 μJ

Fig. 5. Test results of spiral phase plate. (a) Picture of spiral phase plate; (b) the optical axis distribution of spiral phase plate; (c) the light field distribution of the output passing through the polarizer when the linear polarized light incident on the spiral phase plate; (d) vortex beam generated by circular polarization incident on the spiral phase plate; (e) interference image of vortex beam and plane wave

Fig. 6. Test results of planar axicon. (a) Picture of planar axicon (D=6 mm); (b) the optical axis distribution of planar axicon (D=2.4 mm); (c) the light field distribution measured at 0.5,1,1.5,2 m after the circular polarization incident on planar axicon (D=6 mm); (d) the light intensity distribution in Fig. 6(c)

Fig. 7. Test results of high-order Bessel beam generator. (a) Picture of high-order Bessel beam generator; (b) simulation results of optical axis distribution; (c) measurement results of optical axis distribution; (d) simulation results of light field distribution at 2.5 m; (e) measurement results of light field distribution at 2.5 m; (f) interference image of high-order Bessel beam and spherical wave; (g) interference image of high-order Bessel beam and plane wave

Fig. 8. Far field light distribution of high-order Bessel beam,the measured distance is 3, 3.5, 4, 4.5 m from left to right

Fig. 9. LIDT fitting curve of high-order Bessel beam generator