Spatiotemporal-dressed optical solitons in hollow-core capillaries

The nonlinear propagation of a laser beam in a hollow-core capillary is studied by solving the spatiotemporal nonlinear propagation equation. Although we assume to initially couple the light into only one high spatial mode of the capillary, we have identified that the beam can propagate as a new type of multi-mode solitonic structure, the spatiotemporal-dressed soliton, which consists of a mixture of spatial modes in which one has most of the energy while the rest of them, with small contributions, module (dress) the propagation of the main spatial mode. As a consequence of such behavior, we observe a clean self-compression process, obtaining a pulse in the single-cycle limit, accompanied by a giant blue dispersive wave and a new type of multi-mode dispersive wave that appears in the mid-IR region. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement