Title

Interactions of quadratic spatial solitons in noncritically phase-matched KNbO3

Authors

Authors

L. Jankovic; H. Kim; S. Polyakov; G. I. Stegeman; C. Bosshard;P. Gunter

Comments

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Abbreviated Journal Title

Laser Phys.

Keywords

POTASSIUM TITANYL PHOSPHATE; GENERATION; EXCITATION; Optics; Physics, Applied

Abstract

The properties of quadratic spatial solitons in geometries for which second harmonic generation is noncritically phase-matched in KNbO3 were investigated experimentally and theoretically. The inherent symmetry of these geometries can be broken by crystal diffraction anisotropy, input beam asymmetry, or the presence of a low intensity noise on the input beam. This symmetry breaking, coupled with using a fundamental frequency beam only as the input to excite the quadratic solitons, leads to spatially anisotropic multisoliton generation. A very chaotic output pattern distribution, resulting from the noise mediated symmetry breaking in the first stage of propagation and the energy exchange processes between the generated multibeams further into the sample, is demonstrated in a KNbO3 sample at high enough input intensities for multiple solitons to form. In addition, noncritical phase matching affords a unique opportunity to investigate soliton interactions for truly identical solitons. In the interaction processes between quadratic solitons, their fundamental and second harmonics affect each other via up-conversion and down-conversion processes involving photons from each beam when the solitons overlap. To study these interactions, a two-beam experiment was performed. The details of these processes as a function of the relative phase between the two solitons were investigated. For coplanar interactions, energy is exchanged between the two solitons due to the interactions except at 0 and pi relative phase. However, to within the experimental accuracy, there was no change in the ratio of the fundamental and harmonic components. For non-coplanar interactions, a third soliton can be formed in the collision under certain conditions. The numerical calculations performed showed good qualitative agreement with the observed collision features.

Journal Title

Laser Physics

Volume

14

Issue/Number

2

Publication Date

1-1-2004

Document Type

Article; Proceedings Paper

Language

English

First Page

264

Last Page

272

WOS Identifier

WOS:000220016000024

ISSN

1054-660X

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