Attosecond metrology

• Published in: Nature (London) Vol. 414; no. 6863; pp. 509 - 513
• Main Authors: Krausz, F, Hentschel, M, Kienberger, R, Spielmann, Ch, Reider, G. A, Milosevic, N, Brabec, T, Corkum, P, Heinzmann, U, Drescher, M
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 29.11.2001; Nature Publishing Group
• Subjects: Doors; Dynamical systems; Dynamics; Electronics; Exact sciences and technology; Femtosecond; Fundamental areas of phenomenology (including applications); Lasers; Metrology; Nonlinear optics; Optics; Physics; Spectra; Ultrafast processes; optical pulse generation and pulse compression; Velocity; Cross correlations; Time resolved spectroscopy; as range; Ultrashort pulse; Ultrafast optics; Optical pulse generation; Nonlinear optics; X ray emission
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/35107000

The generation of ultrashort pulses is a key to exploring the dynamic behaviour of matter on ever-shorter timescales. Recent developments have pushed the duration of laser pulses close to its natural limit-the wave cycle, which lasts somewhat longer than one femtosecond (1 fs = 10-15 s) in the visible spectral range. Time-resolved measurements with these pulses are able to trace dynamics of molecular structure, but fail to capture electronic processes occurring on an attosecond (1 as = 10-18 s) timescale. Here we trace electronic dynamics with a time resolution of </= 150 as by using a subfemtosecond soft-X-ray pulse and a few-cycle visible light pulse. Our measurement indicates an attosecond response of the atomic system, a soft-X-ray pulse duration of 650 +/- 150 as and an attosecond synchronism of the soft-X-ray pulse with the light field. The demonstrated experimental tools and techniques open the door to attosecond spectroscopy of bound electrons.