Orbital angular momentum 25 years on [Invited]

Abstract

Twenty-five years ago Allen, Beijersbergen, Spreeuw, and Woerdman published their seminal paper establishing that light beams with helical phase-fronts carried an orbital angular momentum. Previously orbital angular momentum had been associated only with high-order atomic/molecular transitions and hence considered to be a rare occurrence. The realization that every photon in a laser beam could carry an orbital angular momentum that was in excess of the angular momentum associated with photon spin has led both to new understandings of optical effects and various applications. These applications range from optical manipulation, imaging and quantum optics, to optical communications. This brief review will examine some of the research in the field to date and consider what future directions might hold.Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. References and links J. H. Poynting, "The wave motion of a revolving shaft, and a suggestion as to the angular momentum in a beam of circularly polarised light," Proc. R. Soc. Lond., A Contain. Pap. Math. Phys. Character 82(557), 560-567 (1909). 2. C. G. Darwin, "Notes on the theory of radiation," Proc. R. Soc. Lond., A Contain. Pap. Math. Phys. Character 136(829), 36-52 (1932). 3. L. Allen, M. W. Beijersbergen, R. J. C. Spreeuw, and J. P. Woerdman, "Orbital angular momentum of light and the transformation of Laguerre-Gaussian laser modes," Phys. Rev. A 45(11), 8185-8189 (1992). 4. J. Courtial, K. Dholakia, L. Allen, and M. J. Padgett, "Gaussian beams with very high orbital angular momentum," Opt. Commun. 144(4-6), 210-213 (1997). 5. A. M. Yao and M. J. Padgett, "Orbital angular momentum: origins, behavior and applications," Adv. Opt.Photonics 3(2), 161-204 (2011). 6. M. Padgett, "Light's twist," Proc. Math. Phys. Eng. Sci. 470(2172), 20140633 (2014). 7. C. Tamm, "Frequency locking of two transverse optical modes of a laser," Phys. Rev. A Gen. Phys. 38(11), 5960-5963 (1988). 8. P. Coullet, G. Gil, and F. Rocca, "Optical vortices," Opt. Commun. 73(5), 403-408 (1989). 9. J. F. Nye and M. V. Berry, "Dislocations in wave trains," Proc. R. Soc. Lond. A Math. Phys. Sci. 336(1605), 165-190 (1974). 10. M. V. Berry, J. F. Nye, and F. Wright, "The elliptic umbilic diffraction catastrophe," Philos. Trans. R. Soc.Lond. A 291(1382), 453-484 (1979). 11. M. W. Beijersbergen, L. Allen, H. E. L. O. van der Veen, and J. P. Woerdman, "Astigmatic laser mode converters and transfer of orbital angular momentum," Opt. Commun. 96(1-3), 123-132 (1993). 12. M. W. Beijersbergen, R. P. C. Coerwinkel, M. Kristensen, and J. P. Woerdman, "Helical-wavefront laser beams produced with a spiral phaseplate," Opt. Commun. 112(5-6), 321-327 (1994 Padgett, D. J. Gauthier, and R. W. Boyd, "High-dimensional quantum cryptography with twisted light," New J.

Orbital-angular-momentum mixing in type-II second-harmonic generation

“…In this context, orbital angular momentum (OAM) has proved to be a potentially useful tool and has motivated a fair amount of research work with potential applications to quantum and classical information processing [1]. In the quantum domain, qubits and qudits can be encoded on Laguerre-Gaussian (LG) or Hermite-Gaussian (HG) modes that combined with the photon polarization allows creation of entanglement between internal photonic degrees of freedom.…”

Twisted-Light–Ion Interaction: The Role of Longitudinal Fields

“…For example, the sub-diffraction-limited focusing of radially polarized beams producing strong longitudinal fields [3] can be used to improve material processing [4,5]. Also, longitudinal fields have seen application in Raman spectroscopy [6], optical tweezers [7], and have been used to observe circular dichroism in non-chiral nanostructures [8].Light carrying orbital angular momentum, known also as twisted light (TL) or optical vortices, has introduced us to a new realm of structured light [9][10][11][12][13]. An unusual property of TL has to do with the relative orientation of the photon's angular momenta.…”

“…Light carrying orbital angular momentum, known also as twisted light (TL) or optical vortices, has introduced us to a new realm of structured light [9][10][11][12][13]. An unusual property of TL has to do with the relative orientation of the photon's angular momenta.…”

Laguerre-Gaussian quasi-modal q-plates from nanostructured glasses

“…3 In addition, the radial structure of LG beams is associated with a radial index p 2 N that remarkably attracted much less interest although its fundamental and applied interest nowadays leaves no doubt. From a practical point of view, the realization of optical components enabling the controlled generation of LG l,p modes is a long-standing issue and we refer to Ref.…”