Spatiotemporal-dressed optical solitons in hollow-core capillaries

Abstract

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.

Soliton Self-Compression and UV Dispersive Wave Emission in Compact Hollow Capillary Systems

“…11 for normal incidence), an incidence of angle of 0.193°maximises the overlap with LP 11 , in good agreement with the simple calculation. At this angle, 39.5 % of the incident energy is coupled into the LP 11 mode.…”

“…However, their small core size (few tens of µm) in combination with intensity limits due to nonlinear effects in the filling gas sets a maximum peak power which can be used to drive soliton dynamics, with typical pulse energies below 20 µJ [4][5][6]9]. Subsequent work proposed that soliton dynamics at higher energy could be achieved by propagating pulses in simple hollow capillary fibres (HCFs) with much larger cores and compensating the resulting reduction in anomalous waveguide dispersion by exploiting higher-order modes [10,11]. It was later demonstrated that the full range of soliton dynamics can in fact be obtained in the fundamental mode of an HCF for correctly chosen parameters [7].…”

Influence of the spatial confinement on the self-focusing of ultrashort pulses in hollow-core fibers

“…In fact, the collapse distance always occurs after the peak power has surpassed P cr during the propagation inside the HCF, as one would expect. The self-compression dynamics presents some features of a standard solitonic self-compression (see 26,27 ), although the process here is more complicated. As in a solitonic process, the self-compression is accompanied by a dispersive wave generation (DWG) (see Fig.…”

High-energy pulse self-compression and ultraviolet generation through soliton dynamics in hollow capillary fibres

“…Theoretical suggestions of how to obtain soliton effects in HCF-which require nonlinearity and dispersion to act simultaneously within the fibre-have included the use of metal-coated HCF to reduce the loss [39], pumping in higherorder modes to increase u nm in Eq. 1 [40,41], or moving to longer wavelengths [42,43]. However, only numerical results on self-compression have been reported so far, with the rich variety of soliton-induced effects remaining unexplored, and no experiments performed to date.…”