Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
The alternative text for this image may have been generated using AI.
Here, spont. stands for spontaneous. a Experimental high-fluence non-linear effects for 25 fs pulses taken from Fig. 2f, h. b Simulated results with our model for similar incident intensity distributions, plotted on the same scale. The shown simulated curves are the black curves in Fig. 3b, c.