Phase singularities and optical vortices in photonics

Abstract

Since the second half of the 20th century, ideas to develop methods for the formation of optical vortices (OVs) or OV beams Ð regions of circular motion of energy flow in an electromagnetic wave around so-called phase singularity points Ð have become widespread. Such optical beams are unique because of the special spiral shape of the wave front, endowing them with orbital angular momentum (OAM) that can be transferred to matter and cause rotation of nano-and micro-objects. Presently, OV beams are actively used to solve both applied and fundamental problems in optics and photonics. We systematically discuss the development stages and the main advantages and disadvantages of methods for the formation of OV beams, from the appearance of phase singularities in light scattering in inhomogeneous media to the latest developments in vortex microlasers for controlled generation of light fields with a predefined OAM on nano-and microscales.

Laser ring structures in step-index fibers

“…Having in mind the nonlinear terms in the equations above (11), we make another pair of substitutions:…”

“…where V , σ, µ, m are new constants. By replacing the expressions (12) in the system (11) and after some transformations, we obtain the following two algebraic equations:…”

“…This kind of vortices are usually studied by a system of two NAEs in scalar form, which characterize the particularities in the evolution of the components of the amplitude function. For the first time, the 3D+1 nonlinear Schrödinger equation for waveguides with a spatial profile of the nonlinear refractive index is solved by the authors in [10,11]. The spatial profile of the linear refractive index results in the generation of laser vortex structures in the field of the components of the intensity of light pulses [12].…”

“…In recent years, significant progress in laser vortex generation has been observed [9,10,11,12]. Important applications of them in active resonators are presented in [13,14,15].…”

Simplifying the Experimental Detection of the Vortex Topological Charge Based on the Simultaneous Astigmatic Transformation of Several Types and Levels in the Same Focal Plane

“…Vortex beams are special structured laser beams, the special properties of which have been actively studied for several decades [ 1 , 2 , 3 , 4 , 5 , 6 ]. The most important among the special properties is the presence of an orbital angular momentum [ 7 , 8 , 9 , 10 , 11 ], which is determined by the order of the optical vortex, also called the topological charge (TC).…”