21 research outputs found
Singular optics and topological photonics
For centuries, singularities in wave fields have been a mainstay of interest in multiple areas of physics, ranging from plasma physics, fluid dynamics and atmospheric physics to optics and photonics [1]. In optics, energy and momentum flow around singularities in the interference field can twist to form vortices, which carry angular momentum [2–4]. Singular Optics is the branch of physics that encompasses studies of structured light with localized and extended singularities, such as optical vortices in scalar optical fields and polarization singularities in vector fields [2, 5, 6]. It has been pioneered by the publication of a seminal paper of Nye and Berry 'Dislocations in wave trains' in 1974 [7], and has recently celebrated its 40th anniversary
Internal flows and energy circulation in light beams
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 spin part associated with the
polarization and orbital part associated with the spatial inhomogeneity. We
give 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. The
emphasize is made 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.Comment: 50 pages, 21 figures, 173 references. This is the final version of
the manuscript (v1) modified in accord to the referee's remarks and with
allowance for the recent development. The main changes are: additional
discussion of the energy flows in Bessel beams (section 4.1), a lot of new
references are added and the Conclusion is shortened and made more accurat
Internal flows and energy circulation in light beams
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