Effect of two-cutoff structure in laser-induced recollision dynamics

•In this work, we are surprised to find that there is a two-cutoff structure in the recollision energy distribution for the third-return trajectory, which is a result of the Coulomb effect to specific recollision trajectories. Especially, the second cutoff induces an extension of the two-dimensional momentum distribution of photoelectrons, which will significantly alter the differential cross-sections (DCS) extracted from LIED and should be taken into account in all kinds of laser-induced imaging schemes based on recollision physics. We theoretically identify a two-cutoff structure in the recollision energy distribution of the third-return recollision trajectories whose contribution is dominant in the high-energy part of the above-threshold ionization (ATI) spectrum. The additional second cutoff in the recollision energy distribution, resulted from the acceleration of Coulomb field to specific recollision trajectories, induces an extension of the Two-dimensional (2D) photoelectron momentum spectrum and will affect the differential cross-sections (DCS) extracted in laser-induced electron diffraction (LIED) scheme. Both the position and relative yield of the second cutoff decrease with increasing laser intensity. Therefore, the effect of the second cutoff should be taken into account when the laser intensity is not so high.