10 August 2007
Vol 317, Issue 5839

About The Cover

Cover image expansion

COVER An array of multilayer mirrors compresses ultrabroadband laser pulses (orange beam) to 1.5 wave cycles. The attosecond x-ray pulses produced with them allow the control and real-time observation of atomic-scale electron motion. See the special section on attosecond spectroscopy beginning on page 765. Photo: Thorsten Naeser for Max Planck Institute for Quantum Optics/Laboratory for Attosecond and High-Field Physics