The effect of an intense laser field on the energies of Auger electrons has been investigated using electron spectroscopy. A laser-generated gallium plasma pumped by a subpicosecond laser yields pulsed broadband x radiation, used to induce LMM Auger transitions in argon. The intense dressing beam ((l = 800 nm) causes the appearance of up to four sidebands on both sides of the original Auger lines. Recording the magnitude of the sidebands versus the time delay between the dressing and x-ray pulses shows that our source delivers subpicosecond pulses in the 250-400 eV range.

Phys. Rev. Lett.

Schins, J. M., Breger, P., Agostini, P., Constantinescu, R. C., Muller, H. G., Grillon, G., … Mysyrowicz, A. (1994). Observation of laser-assisted Auger decay in argon. Phys.Rev.Lett., 73, 2180–2183.