Phase Singularities to Polarization Singularities

Abstract

Polarization singularities are superpositions of orbital angular momentum (OAM) states in orthogonal circular polarization basis. The intrinsic OAM of light beams arises due to the helical wavefronts of phase singularities. In phase singularities, circulating phase gradients and, in polarization singularities, circulating ϕ12 Stokes phase gradients are present. At the phase and polarization singularities, undefined quantities are the phase and ϕ12 Stokes phase, respectively. Conversion of circulating phase gradient into circulating Stokes phase gradient reveals the connection between phase (scalar) and polarization (vector) singularities. We demonstrate this by theoretically and experimentally generating polarization singularities using phase singularities. Furthermore, the relation between scalar fields and Stokes fields and the singularities in each of them is discussed. This paper is written as a tutorial-cum-review-type article keeping in mind the beginners and researchers in other areas, yet many of the concepts are given novel explanations by adopting different approaches from the available literature on this subject.

Self-referenced interferometry for single-shot detection of vector-vortex beams

“…No additional change in the experimental set-up or alignment is required for detection of high-order VV beams. Polarization singular points can be characterized into two types; C-points and V-points 49 . The proposed method is suitable for VV beams that hold V-point.…”

“…Optical vortices are classified as either scalar or vector, based on the polarization distribution surrounding the singularity point 12 , 49 , 62 . Shear interferometry involves interference between the input beam and its wavefront split copy.…”

“…Previous works have shown the use of self-referenced interferometry for the detection of scalar vortices 47 , 48 . Many other approaches have also been reported for the analysis of phase and polarization singularities 49 – 51 . Usually, a polarimetric method is used for the detection of VV beams 52 – 55 .…”

Engineering phase and polarization singularity sheets

“…The process for engineering 2D phase-singularity sheets is also directly applicable to engineering 2D polarization singularity sheets. A detailed review of the connection between phase and polarization singularities is provided by Ruchi et al 32 . Polarization singularities can take multiple forms, but here we focus on C-point singularities in which the polarization azimuth Ψ (in a paraxial field, with negligible E z contribution) is singular 12,33 .…”

High-Accuracy Surface Profile Measurement Based on the Vortex Phase-Shifting Interferometry

“…e new structured light carrying orbital angular momentum (OAM), also known as vortex beam due to its spiral phase structure and phase singularity, is one of the research focuses in optical domain [1][2][3]. e optical orbital angular momentum theoretically provides an infinite multidimensional orthogonal basis, which can be used for information coding [4] and optical communication [5][6][7].…”