Fig. 1. Processes of the reverse ladder transition.

Fig. 2. Process of PA for the target state |9,0〉 in two laser pulses. (a) The total electric field of two laser pulses. (b) The time-dependent population distributions for rovibrational states. (c) The population distributions of the intermediate and background states at the end of laser pulses.

Fig. 3. Time-dependent population distributions versus the amplitude E1 of the first pulse for the target state |9,0〉.

Fig. 4. Time-dependent population distributions versus the amplitude E2 of the second pulse for the target state |9,0〉.

Fig. 5. Processes of PA for the target states |8,0〉 and |7,0〉 in two laser pulses. (a) The total electric field for the target state |8,0〉. The parameters of the second pulse are E2=168.69  MV/cm, τ2=1.35  ps, t2=0  ps, and ω2=6528.29  cm−1. (b) The total electric field for the target state |7,0〉. Parameters of the second pulse are E2=374.38  MV/cm, τ2=2.88  ps, t2=0  ps, and ω2=9056.01  cm−1. (c) and (d) The time-dependent population distributions for rovibrational states.

Fig. 6. Process of PA for the target state |0,0〉 in four laser pulses. (a) The total electric field of four laser pulses. (b) The time-dependent population distributions for rovibrational states.