Controllable supercontinuum generation by the quantum wake of molecular alignment

We demonstrate the generation of supercontinuum with controllable cutoff extension in ultraviolet spectral region through femtosecond filamentation in parallel aligned CO₂ molecules. The additional cross-focusing effect from the quantum wake of impulsive molecular alignment and the subsequently enhanced self-phase-modulation as well as self-steepening and space-time focusing play important roles for the observed supercontinuum generation, which also result in a self-cleaned beam profile by attracting almost all the energy into a single core.