We theoretically study strong-field ionization dynamics under a two-color laser field composed of a strong 800-nm circularly polarized field and a weak 400-nm linearly polarized field. By numerically solving the three-dimensional time-dependent Schrödinger equation, we obtain the photoelectron momentum distributions at different two-color relative phases. These distributions are analyzed using two-color phase-of-the-phase (POP) spectroscopy, yielding both the Relative-Phase Contrast (RPC) and POP spectra, which exhibit pronounced angular and energy dependencies. We demonstrate that when the relative phase of the two-color field takes the value of the POP, the synthesized field effectively mimics an 800-nm elliptical field with the ellipticity dictated by the intensity ratio of the two colors. This mapping enables the angle-dependent POP spectrum to encode the temporal dynamics of ionization induced by a strong elliptical field, from which we reconstruct the ionization time in such a field. Furthermore, we derive an analytic expression for the RPC and show that the RPC spectrum carries information about the imaginary phase of electrons accumulated during strong-field tunneling by elliptical fields. Our work provides an approach to probe ultrafast ionization dynamics in strong elliptical pulses.

Close

PrevNext

View figure in article

• Atomic & molecular processes in external fields
• Multiphoton or tunneling ionization & excitation