Generation of 2.5 μJ vacuum ultraviolet pulses with sub-50 fs duration by noncollinear four-wave mixing in argon

Generation of sub-50fs vacuum UV pulses with more than 2.5μJ energy at a 1kHz repetition rate is reported. The pulses at 160nm are produced using noncollinear difference-frequency four-wave mixing between the fundamental and third harmonics of an amplified Ti:sapphire laser in argon. While the pulse duration is maintained by increasing the phase-matching pressure, noncollinear interaction improves the conversion efficiency by 1 order of magnitude in comparison with the previous results in collinear geometry.