Temporal pulse shaping technique for nonlinear frequency shifting

We present a spectral phase-only shaping technique allowing to generate arbitrary temporal shapes and demonstrate its use for ultrafast ytterbium-based laser sources. This technique is based on the introduction of a nonlinear chirp that is determined solely by the input spectral intensity and the target temporal intensity. We describe its working principle and experimentally demonstrate the generation of triangle-shaped pulses at the output of a laser source, which delivers 150 μ J, sub-200 fs pulses at 150 kHz. These pulses are then passed through a nonlinear multipass cell to observe wavelength shifting via self-phase modulation. A spectral tunabibility of 14 nm is achieved around the input central wavelength of 1034 nm.