Study on the collinear delay double pulse laser induced air plasma expansion by optical interference

In this paper, the air plasma expansion dynamics induced by collinear delayed double nanosecond laser pulses are studied by optical interference method, and comparative analyzed the difference of the air plasma expansion generated by single pulse laser and collinear delayed double pulse laser. The experimental results show that the air plasma expansion distance, expansion velocity and shock wave pressure produced by collinear delay double pulse laser are all larger than that of single pulse because of existing the second laser pulse interaction with the air plasma formed by the first one, and the plasma action time is effectively delay. Finally the mechanisms of the inter-pulse delay time effect on air plasma expansion process are analyzed.