Third harmonic generation by a low intensity laser pulse in a corrugated discharge capillary

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 μm, the third harmonic was generated at intensities as low as ～10~9 W/cm~2.