摘要
Propagation of intense femtosecond laser pulses （60 fs, 800 nm, 120 m J, 6 × 10^17 W/cm^2 in vacuum） in supersonic （CD4）N and （D2）N cluster jets at different backing pressures was studied. Pump-probe interferometry is employed to investigate the propagation of laser beams in dense cluster jets by examining the electron density distribution of plasma chan- nels. It was found that propagation effects, including ionization-induced defocusing and laser attenuation of incident pulses, are very different in the （CD4）N and （D2）N cluster jets. Different ionization states of CD4 and D2 molecules were observed by analyzing the transverse electron density profiles of the plasma channels and should be considered as a major reason for the differences in the propagation effects. Numerical simulations of the nonlinear propagation of femtosecond laser pulses in （CD4）N and （D2）N cluster jets were performed, and the results indicated a good reproduction of the experimental data.
Propagation of intense femtosecond laser pulses （60 fs, 800 nm, 120 m J, 6 × 10^17 W/cm^2 in vacuum） in supersonic （CD4）N and （D2）N cluster jets at different backing pressures was studied. Pump-probe interferometry is employed to investigate the propagation of laser beams in dense cluster jets by examining the electron density distribution of plasma chan- nels. It was found that propagation effects, including ionization-induced defocusing and laser attenuation of incident pulses, are very different in the （CD4）N and （D2）N cluster jets. Different ionization states of CD4 and D2 molecules were observed by analyzing the transverse electron density profiles of the plasma channels and should be considered as a major reason for the differences in the propagation effects. Numerical simulations of the nonlinear propagation of femtosecond laser pulses in （CD4）N and （D2）N cluster jets were performed, and the results indicated a good reproduction of the experimental data.
基金
supported by the National Basic Pesearch Program of China (No. 2006CB806000)
National Natural Science Foundation of China (Nos. 10674145, 60921004, 10974214)
