A novel method of detecting the spectral width and wavelength of extreme ultraviolet (XUV) pulses with a minimum number of experimental tools is demonstrated. The method relies on the photoionization probability of an atom as a function of the electric field. A tunable laser source in the XUV is used that is based on higher-harmonic generation of the frequency-doubled output of a ~50-fs Ti:sapphire laser. The bandwidth and the wavelength of the seventh harmonic 57 nm are detected with Ne, and the resolving power is l / D l =105.

Opt. Lett.

Warntjes, J. B. M., Gürtler, A., Osterwalder, A., Rosca-Pruna, F., Vrakking, M. J. J., & Noordam, L. D. (2001). Atomic spectral detection of tunable extreme ultraviolet pulses. Opt. Lett., 26, 1463–1465.