Tools for numerical modelling of nonlinear propagation in hollow capillary fibres and their application

Abstract

Abstract The development of new coherent and ultrashort light sources is of great relevance for exploring fundamental processes and different applications in science. The most successful technique for generating ultrashort laser pulses, in terms of energy and pulse duration, is using hollow capillary fibre (HCF) compressors. The different strategies to further increase the pulse energy and to achieve shorter pulses at non-conventional wavelengths, lead to continuous improvement of this technique. In this work, we present the theoretical framework of the nonlinear propagation in HCFs through the propagation equation and the spatio-temporal effects that appear in the nonlinear dynamics. To numerically study the nonlinear propagation of the pulse in the HCF, we present different numerical models considering only the spatial effects, (1 + 1)D model, the full spatio-temporal dynamics and ionization, (2 + 1)D model, or the case with lack of cylindrical symmetry, (3 + 1)D model. To show the performance of some of these models in a particular case, we study the generation of ultrashort and energetic dispersive waves (DWs) inside the HCF. We show that the emission of a DW at a fixed wavelength for different pump wavelengths is possible by parameter scaling.