1. Beth, R. A., "Mechanical detection and measurement of the angular momentum of light," Physical Review, Vol. 50, No. 2, 115-125, 1936.
2. Wang, J., J. Y. Yang, I. M. Fazal, N. Ahmed, Y. Yan, H. Huang, et al. "Terabit free-space data transmission employing orbital angular momentum multiplexing," Nature Photonics, Vol. 6, No. 7, 488-496, 2012.
3. Liu, K., Y. Cheng, Y. Gao, X. Li, Y. Qin, and H. Wang, "Super-resolution radar imaging based on experimental OAM beams," Applied Physics Letters, Vol. 110, No. 16, 164102, 2017.
4. Allen, L., M. W. Beijersbergen, R. J. Spreeuw, and J. P. Woerdman, "Orbital angular momentum of light and the transformation of Laguerre-Gaussian laser modes," Physical Review & Atomic Molecular & Optical Physics, Vol. 45, No. 11, 81-85, 1992.
5. Gibson, G., et al. "Free-space information transfer using light beams carrying orbital angular momentum," Optics Express, Vol. 12, No. 22, 5448-5456, 2004.
6. Grier, G. and M. D. Grier, "A revolution in optical manipulation," Nature, Vol. 424, No. 6950, 810-816, 2003.
7. Anzolin, G., F. Tamburini, A. Bianchini, G. Umbriaco, and C. Barbieri, "Optical vortices with starlight," Astronomy & Astrophysics, Vol. 488, No. 3, 1159-1165, 2008.
8. Berkhout, G. C. G. and M. W. Beijersbergen, "Method for probing the orbital angular momentum of optical vortices in electromagnetic waves from astronomical objects," Physical Review Letters, Vol. 101, No. 10, 100801, 2008.
9. Guan, B., C. Qin, R. P. Scott, N. K. Fontaine, T. Su, R. Proietti, et al. "Polarization diversified integrated circuits for orbital angular momentum multiplexing," IEEE Photonics Technology Letters, Vol. 27, No. 10, 1056-1059, 2015.
10. Thidé, B., et al. "Utilization of photon orbital angular momentum in the low-frequency radio domain," Physical Review Letters, Vol. 99, No. 8, 087701, 2007.
11. Mohammadi, S. M., et al. "Orbital angular momentum in radio - A system study," IEEE Transactions on Antennas & Propagation, Vol. 58, No. 2, 565-572, 2010.
12. Tamburini, F., et al. "Experimental demonstration of free-space information transfer using phase modulated orbital angular momentum radio," Physics, Vol. 13, No. 2, 20-25, 2013.
13. Brousseau, C., K. Mahdjoubi, O. Emile, and W. Wei, "Generation of OAM waves with circular phase shifter and array of patch antennas," Electronics Letters, Vol. 51, No. 6, 442-443, 2015.
14. Gaffoglio, R., A. Cagliero, A. D. Vita, and B. Sacco, "OAM multiple transmission using uniform circular arrays: Numerical modeling and experimental verification with two digital television signals," Radio Science, Vol. 51, No. 6, 645-658, 2016.
15. Bai, Q., A. Tennant, B. Allen, and M. U. Rehman, "Generation of Orbital Angular Momentum (OAM) radio beams with phased patch array," Antennas & Propagation Conference, Vol. 9, No. 6, 410-413, 2014.
16. Tamburini, F., et al. "Encoding many channels in the same frequency through radio vorticity: First experimental test," New Journal of Physics, Vol. 14, No. 3, 811-815, 2011.
17. Zhang, Z., S. Zheng, X. Jin, H., Chi, and X. Zhang, "Generation of plane spiral OAM waves using traveling-wave circular slot antenna," IEEE Antennas & Wireless Propagation Letters, Vol. 16, 8-11, 2016.
18. Zhang, W., S. Zheng, X. Hui, Y. Chen, X. Jin, H. Chi, et al. "Four-OAM-mode antenna with traveling-wave ring-slot structure," IEEE Antennas & Wireless Propagation Letters, Vol. 16, 521-524, 2017.
19. Barbuto, M., F. Trotta, F. Bilotti, and A. Toscano, "Circular polarized patch antenna generating orbital angular momentum," Progress In Electromagnetics Research, Vol. 148, 23-30, 2014.
20. Liang, J. and S. Zhang, "Orbital Angular Momentum (OAM) generation by cylinder dielectric resonator antenna for future wireless communications," IEEE Access, Vol. 4, 9570-9574, 2016.
21. Mao, F., M. Huang, T. Li, J. Zhang, and C. Yang, "Broadband generation of orbital angular momentum carrying beams in RF regimes," Progress In Electromagnetics Research, Vol. 160, 19-27, 2017.
22. Yu, S., L. Li, G. Shi, C. Zhu, X. Zhou, and Y. Shi, "Design, fabrication, and measurement of reflective metasurface for orbital angular momentum vortex wave in radio frequency domain," Applied Physics Letters, Vol. 108, No. 12, 5448, 2016.
23. Yu, S., G. Shi, C. Zhu, and Y. Shi, "Generating multiple orbital angular momentum vortex waves using a metasurface in radio frequency domain," Appl. Phys. Lett., Vol. 108, No. 24, 241901, 2016.
24. Jin, J., et al. "Generation and detection of orbital angular momentum via metasurface," Scientific Reports, Vol. 6, 24286, 2016.
25. Chen, M. L. N., L. J. Jiang, and W. E. I. Sha, "Artificial perfect electric conductor-perfect magnetic conductor anisotropic metasurface for generating orbital angular momentum of microwave with nearly perfect conversion efficiency," Journal of Applied Physics, Vol. 119, No. 6, 064506, 2016.
26. Chen, M. L. N., L. J. Jiang, and W. E. I. Sha, "Ultrathin complementary metasurface for orbital angular momentum generation at microwave frequencies," IEEE Transactions on Antennas & Propagation, Vol. 65, No. 1, 396-400, 2017.
27. Chen, M., L. J. Jiang, and W. E. I. Sha, "Detection of orbital angular momentum with metasurface at microwave band," IEEE Antennas & Wireless Propagation Letters, Vol. 17, No. 1, 110-113, 2018.
28. Xu, H. X., H. Liu, X. Ling, Y. Sun, and F. Yuan, "Broadband vortex wave generation using multimode pancharatnam-berry metasurface," IEEE Transactions on Antennas & Propagation, Vol. 65, No. 12, 7378-7382, 2017.
29. Zhang, Y., L. Yang, H. Wang, X. Zhang, and X. Jin, "Transforming surface wave to propagating OAM vortex wave via flat dispersive metasurface in radio frequency," IEEE Antennas & Wireless Propagation Letters, Vol. 17, No. 1, 172-175, 2018.
30. Yu, N., et al. "Light propagation with phase discontinuities reflection and refraction," Science, Vol. 334, 333-337, 2011.