Asymptotically one dimensional dynamics of high peak power ultrashort laser pulses
Laser fields with peak powers P well above the critical power of self focusing P cr are intrinsically unstable with respect to modulation instabilities, breaking up into multiple filaments as a part of a quintessentially three dimensional nonlinear beam dynamics. Here, however, we show that even for P P cr the spatiotemporal field evolution can stay effectively one dimensional. In this regime, observed as an asymptotic case of large diffraction lengths, the laser field can undergo a rich diversity of pulse transformation scenarios, including, most notably, pulse self compression to subcycle field waveforms with very high peak powers, while remaining decoupled, within a limited propagation length, from beam dynamics.