Ultrashort spatiotemporal optical solitons in quadratic nonlinear media: Generation of line and lump solitons from few-cycle input pulses

TL;DR

This paper derives a Kadomtsev-Petviashvili evolution equation for femtosecond spatiotemporal optical solitons in quadratic nonlinear media beyond the slowly varying envelope approximation, demonstrating formation and stability of line and lump solitons through simulations.

Contribution

It introduces a new theoretical framework for modeling ultrashort optical solitons in quadratic media and shows their stable formation from few-cycle pulses.

Findings

Stable line solitons form in normal dispersion media.

Stable lump solitons form in anomalous dispersion media.

Unstable line solitons decay into lumps under perturbation.

Abstract

By using a powerful reductive perturbation technique, or a multiscale analysis, a generic Kadomtsev-Petviashvili evolution equation governing the propagation of femtosecond spatiotemporal optical solitons in quadratic nonlinear media beyond the slowly varying envelope approximation is put forward. Direct numerical simulations show the formation, from adequately chosen few-cycle input pulses, of both stable line solitons (in the case of a quadratic medium with normal dispersion) and of stable lumps (for a quadratic medium with anomalous dispersion). Besides, a typical example of the decay of the perturbed unstable line soliton into stable lumps for a quadratic nonlinear medium with anomalous dispersion is also given.