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Abstract

The nature of electronic motion and structural information of atoms and molecules is encoded into strong-field-induced radiation ranging from terahertz (THz) to extreme ultraviolet wavelength. The dependence of THz yields in bichromatic laser fields on ellipticity and interpulse phase delay was experimentally measured, and the trajectory calculations establish the link between the THz emission and the motion of the photoelectron wave packet. The interaction between the photoelectron and the parent core transforms from a soft collision to recollision as the laser field is tuned from elliptical to linear polarization, which can be reflected in THz emission. The soft collision is found to be more effective in reconstructing electron dynamics through THz polarization, which enables us to construct the effective core potential of the generating medium with the Coulomb-reshaped THz radiation in an elliptically polarized laser field. Our work enables us to design innovative all-optical THz measurements of electronic and structural dynamics.