A creative group of researchers has performed single-shot measurements of ultrafast extreme ultraviolet (EUV) pulses for the first time ever at the FERMI Free Electron Laser (FEL) source in Italy – and these sources aren’t easy to measure. FELs emit intense laser pulses that last less than 100 fs and are composed of wavelengths deep in the UV, well beyond the range and speed of any conventional detector. Furthermore, their characteristics can vary considerably from one pulse to the next. By cleverly adapting the FROG technique used to measure ultrashort lasers at visible wavelengths, the team was able to extract both spectrum and pulse shape, paving the way for further development of FEL sources and benefiting research studies performed using this light.