Generation of high-fidelity, down-chirped sub- 10 fs mJ pulses through filamentation for driving relativistic laser-matter interactions at 1 kHz

The authors present a simple add on for multicycle, multimJ Ti:sapphire-based amplifier systems to efficiently generate 9.5 fs pulses with 1.8 mJ . Filamentary propagation yields spectrally broadened pulses carrying an unexpected large group-delay dispersion of − 500 fs 2 which allows linear propagation of the few-cycle pulses towards target areas without need of any sophisticated dispersion control. Pulse compression could easily be achieved by transmission through a combination of different glass substrates. The pulse wave front, the low energy fluctuations, and the good temporal contrast make this source well suited for relativistic laser-solid experiments with intense few-cycle pulses at kilohertz repetition rate.