GENERATION OF THE 2ND-HARMONICS AND 3RD-HARMONICS IN A LASER-PRODUCEDPLASMA WITH 1-KHZ 90-FS LIGHT-PULSES

Generation of the second and third harmonics of a Ti:sapphire laser in the plasma of self-induced optical breakdown in atmospheric air is st udied. The efficiency of third-harmonic generation up to 1.2 x 10(-3) is achieved in the field of 1-kHz laser pulses with a pulse duration o f 90 fs and a pulse energy of 1 mJ. A spatial structure characteristic of self-phase modulation is revealed in the intensity distribution of the light beam transmitted through the plasma. The self-action of lig ht is demonstrated to have a noticeable influence on the energies of t he second and third harmonics as functions of the energy of fundamenta l radiation.