Higher-order- and multimode properties of nonlinear multipass cells for temporal compression

Over the last few years, temporal compression in nonlinear multipass cells (MPCs) has been proven to be a very promising method for future ultrafast laser sources. Although the majority of the work has been done with Gaussian beams, a few studies have touched upon using structured beams in such subsystems. Here, based on coupled-mode theory and numerical simulations, we focus on the behavior of MPCs upon excitation with either a single higher-order spatial mode or a combination of such modes. This includes their nonlinear properties, linear spatial dynamics upon propagation, and selection rules for efficient nonlinear energy transfer between modes. In particular, we show that the use of high-angular-order Laguerre–Gauss modes should prove efficient to scale the pulse energy inside MPCs.