[en] We propose a scheme for achieving molecular orientation steered by the combination of a nonresonant two-color femtosecond laser pulse and a time-delayed THz laser pulse. It is shown that the molecular negative and positive orientation can be significantly enhanced by applying this scheme compared to the single femtosecond or THz laser pulse. The effects of the intensity of the two-color femtosecond laser pulse and the delay time between the femtosecond laser pulse and the THz laser pulse on molecular orientation are discussed. The molecular orientation also depends on the carrier-envelope phase of the THz laser pulse and the initial rotational temperature of the molecule. The maximal negative and positive orientation degrees calculated are ${⟨<!--\; ???\; -->\text{cos}\mathrm{\theta <!--\; ??\; -->}⟩<!--\; ???\; -->}_{\text{nmax}}=0.828$ and ${⟨<!--\; ???\; -->\text{cos}\mathrm{\theta <!--\; ??\; -->}⟩<!--\; ???\; -->}_{\text{pmax}}=0.755$, respectively. (paper)

[en] We investigated the Autler–Townes splitting in photoelectron spectra of $\text{L}{\text{i}}_2$ molecules steered by ultrashort laser pulses using the time-dependent wave-packet method. Structure of the Autler–Townes splitting was presented to analyze the information of a selective population of the dressed states. It was found that population transfer process, structure of photoelectron spectrum and pattern of Autler–Townes splitting can be controlled by adjusting the intensity, wavelength and delay time of laser pulses. (paper)

[en] The population transfer of a NaH molecule from the ground state $X^1{\mathrm{\Sigma <!--\; ??\; -->}}^{+}$ to the target state $A^1{\mathrm{\Sigma <!--\; ??\; -->}}^{+}$ via stimulated Raman adiabatic passage (STIRAP) is investigated. The results show that the intensity, delay time and detuning have a significant effect on population transfer. A large population transfer is observed with increased pump and Stokes intensity, especially when the pump and Stokes intensity match. Population transfer also depends on the delay time between the pump laser pulse and the Stokes laser pulse. The detuning of the two pulses influences the population transfer. Efficient population transfer can be realized under the resonant or two-photon resonant condition. (paper)