Observation of Laser-Assisted Dynamic Interference by Attosecond Controlled Photoelectron Spectroscopy

We have observed the laser-assisted dynamic interference in the electron spectra triggered by attosecond pulse trains. The fingerprints of finer interference fringes, much smaller than the laser photon energy, have been clearly identified experimentally. Our measurements are successfully reproduced by theoretical simulations utilizing the numerical solution to the time-dependent Schrödinger equation and the strong-field approximation. Further explorations based on the saddle point analysis and a simple quantum model strengthen our finding and reveal the importance of the phase variations of the electron wave packets, which are modulated by the vector potential across the envelope of the strong laser pulse. Our studies show that the dynamic interference can be captured and the electron in the continuum can be effectively manipulated by the current attosecond-controlled multicolor laser approach.