Temporal pulse shaping technique for nonlinear frequency shifting

Gautier Parize^1,2, Michele Natile¹, Florent Guichard¹, Antoine Comby¹, Marc Hanna², and Patrick Georges²
1. Amplitude, Cité de la Photonique, 11 Av. de Caneranne, 33600 Pessac, France
2. Université Paris-Saclay, Institut d’Optique Graduate School, CNRS, Laboratoire Charles Fabry, 2 Av. Augustin Fresnel, 91127 Palaiseau, France

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, as shown in Fig 1.

Figure 1: Top - spectrum (black) and applied delay (dashed green) via spectral phase control. Bottom - Resulting temporal profile (green) and target temporal profile (black).

We describe its working principle and experimentally demonstrate the generation of triangle shaped pulses at the output of a laser source, which delivers 150 µJ, 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 tunability of 28 nm is achieved around the input central wavelength of 1034 nm.