Power-dependent shaping of vortex solitons in optical lattices with spatially modulated nonlinear refractive index

Abstract

We address vortex solitons supported by optical lattices featuring modulation of both the linear and nonlinear refractive indices. We find that when the modulation is out of phase the competition between both effects results in remarkable shape transformations of the solitons that profoundly affect their properties and stability. Nonlinear refractive index modulation is found to impose restrictions on the maximal power of off-site solitons, which are shown to be stable only below a maximum nonlinearity modulation depth.

Power-dependent shaping of solitons in parity time symmetric potentials with spatially modulated nonlinearity

“…In the meantime, the spatially modulated nonlinearity or its combination of linear refractive index can substantially affect the existence and stability of solitons [17][18][19][20][21][22][23][24][25][26][27][28]. Bound states with an arbitrary number of solitons [17], surface solitons [18][19][20][21], multipole solitons [22], vortex solitons [22][23][24], necklace solitons [25], vector solitons [26], and light bullets [27,28] have been theoretical studied in optical lattices with spatially modulated nonlinearity (for the topic of nonlinear lattices, see also [29]).…”

Stable Higher-Charged Vortex Solitons in Optically-Induced Lattices

“…Successful alternatives are confined systems, such as graded-index optical fibers [12], nonlinear photonic crystals with defects [13], linear and nonlinear optical lattices [14][15][16][17][18][19], or optical lattices with defects [20], where the azimuthal instability of vortices can be suppressed by the corresponding confining potentials. Stable vortices with charges lower than two are possible within certain ranges of lattice (transverse refractive index modulation) parameters [14,17,[21][22][23][24][25][26][27][28].…”

“…Very recently, various types of one-dimensional solitons in the form of odd, even, dipole, triple, vector solitons, and two-dimensional solitons in the form of fundamental, multi-pole, vortex, surface solitons, and three-dimensional solitons in the form of light-bullets and optical tandems were predicted in competing linear and nonlinear lattices [18,[62][63][64] or in purely nonlinear lattices [19,[65][66][67]. On the other hand, spatially modulated nonlinearity may result in controllable soliton shape transformations [18,62].…”

“…On the other hand, spatially modulated nonlinearity may result in controllable soliton shape transformations [18,62]. Bound states with an arbitrary number of solitons can be found in media with spatially inhomogeneous nonlinearities [68].…”

“…They revealed that the stability domain of necklace solitons expands with the increase of the number of necklace spots. Although vortex solitons in linear-nonlinear or in purely nonlinear lattices were studied in [18,19], the discussions were limited to the vortices with unit charge. In fact, stable localized vortex solitons with charges higher than two were only predicted in media modulated by Bessel-like lattices [25,26].…”