<title>Optical wavefront dislocations</title>

Abstract

We report the result of investigation of the screw, edge and mixed edge-screw dislocations of wavefront in monothromatic light waves. Methods for the experimental determination of the topological charge value and helicity of screw dislocation are elaborated. By use of computer-synthesized binary gratings waves with edge, mixed screw-edge and anisotropic screw dislocation were obtained and Studied experimentally. 1JNTRODUCTIONIn last years optical wavefront dislocations (phase singularities, or optical vortices) attract a great attention15. First analysis and description of phase defects in wave train and monochromatic wave was perfonned in a paper of Nye and Berry'. The presence of screw dislocations in speckle field was demonstrated later. The optical waves possessing single screw dislocation or a system of several dislocations were experimentally obtained in laser cavities3'4 oscillation, diffraction by specially synthesized holograms57, transmission of light beams through phase mask8'9, observed in laser light scattered by random phase diffuser or transmitted through multimode fibers.Existence ofthe phase singularity in an optical wavefront requires that the amplitude Eofthe light wave vanishes at this point, so as real, as imaginary part ofcomplex amplitude are equal to zero and phase becomes indeterminate.Our aim is to give general rule for the determination of sign and topological charge of the screw dislocation and to report the analytical approach and experiments with holographically synthesized waves possessing edge, mixed screwedge and anisotropic screw dislocations.

Opto-Electronics Review

“…On the other hand, the optical singularities (as well as the patterns of DCs, by the way) are, generally, not immediately perceptible (sometimes they can be detected as the amplitude zeros, but in other cases this association can be elusive). As a rule, the singularities are detected indirectly via the interference with special "reference" waves of the simple standard structure [35][36][37][38][39], which puts no principal difficulties for the modern optical techniques. Anyway, the physical contents and technical possibilities associated with their wide use for the optical field inspection and characterization justify any effort directed to a deeper study of optical rotations and singularities.…”

<title>Random optical fields: fractal-like fluctuations and scale effects</title>

“…This allows to interpret amplitude (and, in certain cases, intensity) fluctuations in the detection point as the generalized Brownian process6 with Hurst parameter equal to 0.25, exponential factor equal to 0.5 and Hausdorff dimension equal to 1.75. So, analyzing the dependencies of these characteristics (Hurst parameter can be estimated as: H = lfl{1_1(t2)}/2Ifl(t2/tl), (1) 1-gi(ti) exponential factor V as 2H, and Hausdorif dimension as Djn 2-H) on scattering geometry and media parameters we can describe in the generalized form stochastization ofthe probe beam field distribution due to the multiple scattering. In this work another case of the formation of scattered fields with fractal properties is considered, when their non-stationarity is caused by the regular movements of the steady-structure scattering objects.…”

Singular Optics: more ado about nothing

“…• The 80th birthday anniversary of Professor Marat Soskin, one of the pre-eminent scientists in this field who coined the term 'Singular Optics' (e.g. [5,6]), and the grandfather of Singular Optics in Ukraine.…”

“…Other research from this period anticipating Singular Optics is discussed in [9]. An important historical landmark from this period is the work of Hans Wolter [37] published in 1950 5 . Although highlighted some years ago by Rosu [38], this work has been largely unnoticed by the Singular Optics community (although see [9]).…”

“…Wolter studies this further by considering, as the incoming beam, a pair of plane waves with slightly different directions, each of which undergoes reflection inside the glass (with a small evanescent component in the air). By considering the geometry of the intensity minima of the incoming and reflected fields (which are used to mark the positions of the beam), Wolter develops a detailed picture 5 2009 thus marking the 60th anniversary of the submission of Wolter's paper! of the intensity and phase distribution, and energy flow in the vicinity of the interface.…”