Spatially engineered polarization states and optical vortices in uniaxial crystals

Abstract

We describe how the propagation of light through uniaxial crystals can be used as a versatile tool towards the spatial engineering of polarization and phase, thereby providing an all-optical technique for vectorial and scalar singular beam shaping in optics. Besides the prominent role played by the linear birefringence, the influence of circular birefringence (the optical activity) is discussed as well and both the monochromatic and polychromatic singular beam shaping strategies are addressed. Under cylindrically symmetric light-matter interaction, the radially, azimuthally, and spirally polarized eigen-modes for the light field are revealed to be of a fundamental interest to describe the physical mechanisms at work when dealing with scalar and vectorial optical singularities. In addition, we also report on nontrivial effects arising from cylindrical symmetry breaking, e.g. tilting the incident beam with respect to the crystal optical axis.

Conical refraction: fundamentals and applications

“…the SOP is identical for all points at any transverse plane along the beam propagation. However, there exist light beams possessing non-homogenous polarization, known as vector beams, such as the well known radial or azimuthal polarizations [101] or even beams with more involving polarization distributions [124][125][126]. The non-homogeneous polarization distribution of vector beams can lead to singular points where the SOP is exactly circular (C points), lines along which the SOP is linear (L lines) or disclinations where the instantaneous electric field is null [127][128][129][130].…”

Raman optical activity by light with spin and orbital angular momentum

“…It is interesting to note that the eigenpolarizations of light propagating along the optic axis of a uniaxial crystal are radial and azimuthal polarization. 11 . A circular polarized LG mode, |±1, ± and |±1, ∓1 can be expressed as the linear superposition of radial and azimuthal polarization with a π/2 phase difference, 9 and as such, may lead to a 'mixing' of the tensor components associated with the orientational and polarization specific Raman scattering spectra of birefringent uniaxial crystal such as quartz.…”

Topological defects of optical indicatrix orientation in optically biaxial crystals. The case of light propagation in the directions close to the optic axes

“…Such singularities can be induced by different inhomogeneous fields [14][15][16][17][18][19] under propagation of nearly parallel beams through crystals or glasses. The effect can be observed if conical beams propagate in optically uniaxial crystals along the optic axis (OA) direction [20][21][22][23][24][25]. The same is true for the case of optically biaxial crystals, provided that the beam propagates along one of the OAs under the conditions of conical refraction [26][27][28].…”