Attosecond X-ray probing of laser-induced electron rescattering in atoms

Abstract

We propose an attosecond time-domain spectroscopy to study laser-induced electron rescattering in atoms by using single photoionization with an attosecond X-ray pulse. From the time-frequency analysis of the time-domain signal, we obtained simultaneously the subcycle time and energy information of the rescattering electron wave packet during the interaction of a helium-like atom with a strong laser field. The obtained time and energy distributions nicely agree with the electron rescattering picture from the analysis based on the high-order harmonic response by the dipole acceleration and classical trajectory calculations. Contributions and interference from multiple rescattering can be unambiguously identified in the time and energy distributions of rescattering electrons. Since the observable of X-ray single photoionization yield is proportional to the electron density near the nucleus, the proposed time-domain spectroscopy can in general be applied to studies of other light-induced linear and nonlinear polarization effects in atoms and molecules.