Attosecond control of electron emission from atoms

[摘要] We demonstrate that the electron emission from atoms can be temporally controlled on an attosecond time scale. Electron wave-packets are formed by ionizing an atomic target with an attosecond pulse train composed of both odd and even high-order harmonics in the presence of a relatively weak infrared field. We show that interference between one- and two-photon transitions produces a large asymmetry in the angular distribution of the photoelectrons. The direction of the emission can be controlled on an attosecond time scale by varying the time delay between the two pulses. In addition, we show that such asymmetric emission is also related to the properties of the attosecond pulse train. The temporal analysis of the modulated electron emission, based on an accurate description of the atomic physics of the photoionization process, then provides a way to measure the temporal profile of the attosecond pulse.

[发布机构] James R. MacDonald Laboratory, Physics Department, Kansas State University, Manhattan; KS; 66506, United States^1;Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge; MA; 02139, United States^2

[关键词] Asymmetric emission;Attosecond pulse trains;Attosecond time scale;Electron wave packet;High order harmonics;Photoionization process;Temporal analysis;Two-photon transitions