Effect of beam of light blocked by laser plasma

Laser-induced air breakdown has arisen when Nd~(3+):YAG laser is focused in the air,using a Nd~(3+): YAG laser with 59.2 ns pulsed train length and 20.69 ns single pulse width.The time graph of incident laser and transmitting laser passing plasma is measured in different laser intensity.Following result are Obtained,because laser is absorbed intensively while passing laser plasma,there is blockade effect of incident laser is.The smaller electron diffusion in the plasma is,the more distinct blockade effect of incident laser is.When Nd~(3+):YAG laser passing plasma twice in the part of experiment,with the length of laser plasma increasing,the blockade effect of incident laser becomes more serious.