Abstract
The pulse shape and phase of isolated attosecond extreme ultraviolet (XUV) pulses with a duration of 860 attosecond (asec) have been determined simultaneously by using frequency-resolved optical gating based on two-photon above-threshold ionization with 28-eV photons in He. From the detailed characterization, we succeeded in shaping isolated XUV pulses on an attosecond time scale either by precise dispersion control with generation gas density (Ar) or by changing the driving pulse width. These results offer a novel way to excite and observe an electron motion in atoms and molecules.