We present the photoelectron momentum distributions (PMDs) and the photoelectron angular distributions (PADs) of He+ ions, aligned H 2 + molecules and N2 molecules by intense orthogonally polarized laser pulses. Simulations are performed by numerically solving the corresponding two-dimensional time-dependent Schrödinger equations (TDSEs) within the single-electron approximation frame. Photoelectron momentum distributions and photoelectron angular distributions present different patterns with the time delays T d, illustrating the dependences of the PMDs and PADs on the time delays by orthogonally polarized laser pulses. The evolution of the electron wavepackets can be employed to describe the intensity of the PADs from the TDSE simulations for N2 molecules.

The strong-field ionization of dimers is investigated theoretically in counter-rotating circularly polarized laser fields. By numerically solving the two-dimensinal (2D) time-dependent Schrödinger equation (TDSE) with the single-electron approximation (SEA) frame, we present the photoelectron momentum distributions (PMDs) and photoelectron angular distribution (PADs) of aligned Ne and Xe dimers. It is found that the PMDs and PADs strongly depend on the time delays by counter-rotating circularly polarized laser pulses. The results can be explained by the ultrafast photoionization model and the evolution of electron wave packets for Ne and Xe dimers. Besides, We make a comparation of PMDs between Ne atom and Ne dimer.

We present a scheme to control the generated ultrafast magnetic field in $\rm H_{3}^{2+}$ molecule by using multi-frequency tricircular pulses composed of co and counter-rotating bicircular pulses. Simulations show that the field amplitude and the wavelength are two significant factors on magnetic field generation by tricircular pulse. Specifically, the strength of magnetic field is linearly related to the field amplitude at $\lambda _{0}$=50 nm, while at $\lambda _{0}$=70 nm, the strength first increases and then decreases with the amplitude, which can be attributed to the resonance between the ground and excited states. Moreover, the phase and helicity of bicircular pulse were shown to have important effects on the magnetic field. The dependence of the magnetic field on the phase arises from the interference effect between multiple ionization pathways. These findings illustrate a guiding principle of controlling the magnetic field in molecular systems for future researches in ultrafast magneto-optics.