Internal flows and energy circulation in light beams

By A. Bekshaev, K. Bliokh, M. Soskin. 2010

313 citations recorded by the source corpus.

We review optical phenomena associated with the internal energy redistribution which accompany propagation and transformations of monochromatic light fields in homogeneous media. The total energy flow (linear-momentum density, Poynting vector) can be divided into a spin part associated with the polarization and an orbital part associated with the spatial inhomogeneity. We give a general description of the internal flows in the coordinate and momentum (angular spectrum) representations for both nonparaxial and paraxial fields. This enables one to determine local densities and integral values of the spin and orbital angular momenta of the field. We analyse patterns of the internal flows in standard beam models (Gaussian, Laguerre–Gaussian, flat-top beam, etc), which provide an insightful picture of the energy transport. Emphasis is given to the singular points of the flow fields. We describe the spin–orbit and orbit–orbit interactions in the processes of beam focusing and symmetry breakdown. Finally, we consider how the energy flows manifest themselves in the mechanical action on probing particles and in the transformations of a propagating beam subjected to a transverse perturbation.

Subfields: Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/9db7473c89da5b8e927fdb8b3af3dc927c6b3c62

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In Atomic and Molecular Physics, and Optics

1. Franco Nori
2. K. Bliokh
3. A. Bekshaev
4. I. Mokhun
5. Zheng Jun
6. C. Zenkova
7. S. Hanson
8. O. Angelsky

Citations in the corpus

• Structured Light: Ideas and Concepts (2020, background): “Still, from the field-theory point of view, the spin–orbital (canonical) momentum decomposition (15)–(17) looks deficient because the separate OM and SM (as well as the SAM and OAM) are not gauge invariant [9, 20, 60].”
• Extraordinary momentum and spin in evanescent waves (2013, background): “In the case of monochromatic electromagnetic waves (photons), equation (3) yields the timeaveraged Poynting vector p1⁄4 gkRe(E H), when Ŝ is given by spin-1 matrices that act on the complex electric and magnetic field”
• Theory and applications of free-electron vortex states (2017, background): “In the past two decades, five books [55, 56, 57, 58, 59] and many reviews [60, 61, 62, 63, 64, 65, 66] about optical vortex beams and OAM were published.”
• Transverse and longitudinal angular momenta of light (2015, background): “The circulation of the canonical momentum immediately yields the orbital AM density in the optical field [14,31,34,37, 50,84]:”
• Transverse spin and momentum in two-wave interference (2014, unknown): “[5,7–10,27,30–32]).”