Approximate solutions and scaling transformations for quadratic solitons

We study quadratic solitons supported by two- and three-wave parametric interactions in chi-2 nonlinear media. Both planar and two-dimensional cases are considered. We obtain very accurate, 'almost exact', explicit analytical solutions, matching the actual bright soliton profiles, with the help of a specially-developed approach, based on analysis of the scaling properties. Additionally, we use these approximations to describe the linear tails of solitary waves which are related to the properties of the soliton bound states.Comment: 11 pages, 9 figures; submitted for publicatio

Cascaded second-order surface plasmon solitons due to intrinsic metal nonlinearity

We theoretically show the existence of cascaded second-order surface plasmon solitons propagating at the interface between metal and linear dielectric. Nonlocal multipole nonlinearities originating from free conduction electron plasma of a metal lead to strong interaction between co-propagating surface plasmon polariton beams at fundamental and second harmonic frequencies. Finite element numerical modelling for effective two-dimensional medium explicitly demonstrates the solitons formation, confirming the theoretical results. The non-diffractive regime of propagation has been demonstrated at silica/silver interface for 5{\lambda} wide surface plasmon polariton beams with the loss-limited propagation distance of the order of 100 um for the 750/1550 nm wavelengths pair. Plasmon-soliton formation in the phasematched conditions has been shown to be beneficial for nondiffractive surface plasmon polariton propagation