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Temporal pulse characterization methods can often not be applied to UV pulses due to the lack of suitable nonlinear crystals and very low pulse energies. Here, a method is introduced for the characterization of two unknown and independent laser pulses. The applicability is broad, but the method is especially useful for pulses in the deep UV, because pulse energies on the picojoule-scale suffice. The basis is a spectral analysis of the two interfering UV pulses, while one of the pulses is phase shifted by an unknown VIS-IR pulse via cross-phase modulation. The pulse retrieval is analytic and the fidelity can be checked by comparing the complex-valued data trace with the retrieved trace.

Noncollinear pulse characterization methods can be applied to over-octave spanning waveforms, but geometrical effects in the nonlinear medium such as beam smearing and critical sensitivity to beam alignment hinder their accurate application. Here, a method is introduced for the temporal and spatial characterization of two pulses by interferometric, spectrally resolved imaging of self-diffraction. Geometrical effects are resolved by the method and, therefore, do not limit the accuracy. Two methods for quantitative pulse retrieval are presented. One method is analytical and very fast; the other method is iterative and more robust if applied to noisy data.

We report on the frequency doubling of femtosecond laser pulses at 1030 nm center wavelength generated from the fully diode-pumped laser system POLARIS. The newly generated pulses at a center wavelength of 515 nm have a pulse energy of 3 J with a pulse duration of 120 fs. On the basis of initially ultra-high contrast seed pulses we expect a temporal intensity contrast better 10 17 200 ps before the peak of the main pulse. We analyzed the temporal intensity contrast from milliseconds to femtoseconds with a dynamic range covering more than 20 orders of magnitude. The pulses were focussed with a f/2-focussing parabola resulting in a peak intensity exceeding 10 20 W/cm 2 . The peak power and intensity are to the best of our knowledge the highest values for 515 nm-laser-pulses achieved so far.

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