Time-resolved spectroscopy for 5s4D7/2 state transitions undergoing electron-ion recombination in femtosecond laser-produced copper plasma

In the femtosecond laser-produced Cu-plasma, the transient transition dynamics that the excited state 5s4D7/2 via electron-ion recombination transfers to 4p4F9/20 （465.11 nm, Λ1 line） and 4p4D7/20 （529.25 nm, Λ2 line） states are investigated by using the time-resolved spectroscopy. The occupation number and relevant lifetime of the excited state 5s4D7/2, the temporal evolutions of spectral intensities for Λ1 line and Λ2 line emissions are demonstrated to be in direct proportion to the employed laser intensity, which reveals the transient features of transition dynamics clearly differing from that resulted in the traditional collision excitation. Furthermore, some unique characteristics for Λ1 and Λ2 transitions stemming from electron-ion recombination are examined in detail.