[摘要]:Quasi phase matching and increase of laser interaction length were promoted by periodically modulated plasma guide formed by a discharge current ablating the inner capillary walls. The phenomenon was demonstrated through the use of third harmonics. For Ti:Sapphire laser pulses propagating through 1 cm long corrugated discharge capillaries, with an axial corrugation period of 200 mu m, the third harmonic was generated at intensities as low as similar to 10(9) W/cm(2). (C) 2011 American Institute of Physics. [doi:10.1063/1.3664221]