Optical vortices in waveguides with discrete and continuous rotational symmetry

Abstract

Coherent vortex structures are fascinating physical objects that are widespread in nature: from large scale atmospheric phenomena, such as tornadoes and the Great Red Spot of Jupiter to microscopic size topological defects in quantum physics and optics. Unlike classical vortex dynamics in fluids, optical vortices feature new interesting properties. For instance, novel discrete optical vortices can be generated in photonic lattices, leading to new physics. In nonlinear optical media, vortices can be treated as solitons with nontrivial characteristics currently studied under the emerging field of topological photonics. Parallel to theoretical advances, new areas of the engineering applications based on light vortices have emerged. Examples include the possibility of carrying information coded in the vortex orbital angular momentum, understood as a spatial-division-multiplexing scheme, to the creation of optical tweezers for efficient manipulation of small objects. This report presents an overview highlighting some of the recent advances in the field of optical vortices with special attention on discrete vortex systems and related numerical methods for modeling propagation in multi-core fibers.

Topological charge of superposition of optical vortices described by a geometric sequence

“…Topological charge of a superposition of optical vortices described by a geometric sequence. Computer Optics 2022; 46 (6): 864-871. DOI: 10.18287/2412-6179-CO-1152.…”

“…В [5] рассматриваются оптические вихри в нанофотонике. Оптические вихри в структурированных волноводах исследуются в [6]. В [7] исследуется искажение оптических вихрей и показано, что оптические вихри почти не чувствительны к искажениям.…”

Spatiotemporal dynamics in a twisted, circular waveguide array

“…2 As it relates to basic research, this optics platform presents an opportunity to theoretically 3 and experimentally 4 explore localized spatiotemporal dynamics (discrete light bullets) in nonlinear discrete systems, localized soliton-like solutions, and other structures such as discrete optical vortices. 5 While most research has been on uniform, equally spaced waveguide arrays, recent technological advances, which allow for more general configurations, have opened new research directions in what is called topological photonics. 6 This is the case, for example, when a twist is imposed on a circular multicore fiber, which in particular allows for fine control of diffraction and light transfer in a similar manner to axis bending in linear waveguide arrays.…”

“…At high intensities, in the nonlinear regime, current research includes generating high power coherent pulses by combining light propagating in each core 2 . As it relates to basic research, this optics platform presents an opportunity to theoretically 3 and experimentally 4 explore localized spatiotemporal dynamics (discrete light bullets) in nonlinear discrete systems, localized soliton‐like solutions, and other structures such as discrete optical vortices 5 . While most research has been on uniform, equally spaced waveguide arrays, recent technological advances, which allow for more general configurations, have opened new research directions in what is called topological photonics 6 .…”

Vortex Solitons in Twisted Circular Waveguide Arrays

“…In nonlinear media, such refractive index landscapes (in particular, periodic geometries) may support rich families of lattice solitons, which have been observed in multi-dimensional geometries [6][7][8][9][10][11][12]. Lattices may suppress azimuthal modulation instabilities, thus stabilizing vortex states (see reviews [13][14][15], experimental realizations [16][17][18][19][20] and theoretical proposals [9,[21][22][23][24][25], including in dissipative systems [26]). Vortices can also exist in structures exhibiting discrete angular rotational symmetry rather than transverse periodicity, such as modulated Bessel lattices [27][28][29][30][31] or photonic crystals [32].…”