Fig. 1. Generation methods of OAM beam. (a) Spatial light modulator^[24]; (b) Q-plate^[25];(c) liquid-crystal Damman vortex grating^[27]; (d) meta-Q-plate^[28]

Fig. 2. OAM beam splitter^[35]

Fig. 3. Separation experimental results of OAM beam^[35]

Fig. 4. Interferometer device relying on Gouy phase^[39]

Fig. 5. Separation detection results of LG beams^[39]

Fig. 6. OAM mode separation based on coordinate transformation^[41]. (a) diffractive element loaded on SLM2; (b) diffractive element loaded on SLM2; (c) diagram of experimental device

Fig. 7. Simulated and observed phase and intensity distributions at various planes in the optical system^[41]

Fig. 8. Coordinate transformation ways^[44]. (a) Log-polar transformation; (b) spiral transformation

Fig. 9. Intensity distributions of different OAM modes^[44]. (a)(b) Numerical simulation and experimental results for polar coordinate transformation; (c)(d) numerical simulation and experimental results for spiral transformation

Fig. 10. Schematic of microscopic device for spiral phase contrast imaging^[49]

Fig. 11. Comparison of traditional bright field imaging and spiral phase contrast imaging results^[49]. (a)(c) Bright field imaging results of objects; (b)(d) corresponding spiral phase contrast imaging results

Fig. 12. Schematic of spiral phase contrast imaging^[62]. (a) Principle of linear optical spiral phase contrast; (b) principle of nonlinear optical spiral phase contrast

Fig. 13. Experimental results of spiral phase contrast imaging^[62]. (a1)--(a7) Pictures of purely phased dog; (b1)--(b7) non-spiral phase contrast images; (c1)--(c7) spiral phase contrast images

Fig. 14. Schematic of frequency shift detection device^[34]

Fig. 15. Results of frequency shift detection^[34]

Fig. 16. Detection of angular velocity of spin objects^[18]. (a) Incidence of superposition beam; (b) experimental results of superposition beam incident; (c) incidence of fundamental mode-Gaussian beam; (d) experimental results of fundamental mode-Gaussian beam incident

Fig. 17. Installation diagram of free-space rotation remote sensing experiment ^[75]

Fig. 18. Power spectra of rotational Doppler shifts^[75]

Fig. 19. Schematic of optical tweezers device

Fig. 20. Spin motion and orbital motion of particle^[96]

Fig. 21. Relationship curves between particle rotation speed and tunable OAM^[103]