What does the Helios use to generate the white light? What are the specifications for this pulse (wavelength, energy)?

The white light is generated by a small (a few %) fraction of the fundamental laser output. The pulse energy for stable continuum generation is usually 1-2 microJ, the wavelength is ca 800 nm or ca 1030 nm. Due to losses on multiple reflections in the routing optics and the delay line assembly the required energy after the corresponding beam splitter should be ~50 microJ.