
April 24, 2014 17:29 PSP Book - 9in x 6in 03-Rashid-A.-Ganeev-c03
90 Low-Order Harmonic Generation in Plasma Plumes
density of the particles becomes sufficient for efficient HG, although
the free electron concentration remains below the level when the
impeding processes prevail over the HG.
The above assumptions and our experimental results show
that optimization of the lowest harmonic allows us defining the
conditions of plasma formation for efficient higher-order HG.
Although the efficiency of THG using picosecond pulses still remains
at the moderate level (due to small intensity of the laser beam
and lower thresholds of multiphoton ionization of particles