Multiple-type solutions for multipole interface solitons in thermal nonlinear media

We address the existence of multipole interface solitons in one-dimensional thermal nonlinear media with a step in the linear refractive index at the sample center. It is found that there exist two types of solutions for tripole and quadrupole interface solitons. The two types of interface solitons have different profiles, beam widths, mass centers, and stability regions. For a given propagation constant, only one type of interface soliton is proved to be stable, while the other type can also survive over a long distance. In addition, three types of solutions for fifth-order interface solitons are found.Comment: 5 pages, 5 figure

Solitons in thermal media with periodic modulation of linear refractive index

We address the existence and properties of solitons in thermal media with periodic modulation of linear refractive index. Many kinds of solitons in such optical lattices, including symmetric and antisymmetric lattices, are found under different conditions. We study the influence of the refractive index difference between two different layers on solitons. It is also found that there do not exist cutoff value of propagation constant and soliton power for shifted lattice solitons. In addition, the solitons launched away from their stationary position may propagate without oscillation when the confinement from lattices is strong.Comment: 6 pages, 6 figure

The Relation Between Optical beams Propagation in Free Space and in Strongly Nonlocal Nonlinear Media

The relation between optical beams propagation in strongly nonlocal nonlinear (SNN) media and {propagation} in free space is {demonstrated using} the technique of variable transformation. The governing equation, integral and analytical solutions, and propagation properties in free space can be directly transferred to their counterparts in SNN media through a one-to-one correspondence. The one-to-one correspondence together with the Huygens-Fresnel integral yields an efficient numerical method to describe SNN propagation. The existence conditions and possible structures of solitons and breathers in SNN media are described in a unified manner by comparing propagation properties in SNN media with those in free space. The results can be employed in other contexts in which the governing equation for the evolution of waves is equivalent to that in SNN media, such as for quadratic graded-index media, or for harmonically trapped Bose-Einstein condensates in the noninteracting limit.Comment: 10 pages, 2 figures, published in EP

Defect solitons supported by nonlocal PT symmetric superlattices

The existence and stability of defect solitons supported by parity-time (PT) symmetric superlattices with nonlocal nonlinearity are investigated. In the semi-infinite gap, in-phase solitons are found to exist stably for positive or zero defects, but can not exist in the presence of negative defects with strong nonlocality. In the first gap, out-of-phase solitons are stable for positive or zero defects, whereas in-phase solitons are stable for negative defects. The dependence of soliton stabilities on modulation depth of the PT potentials is studied. It is interesting that solitons can exist stably for positive and zero defects when the PT potentials are above the phase transition points.Comment: 12 figures, 6 pages, Accepted by EP