ABSTRACT
Earliest observations of the HHG in gases were reported using the
picosecond lasers [1-3]. The harmonics from different gases up to
the 21st and 33rd orders of 1064 nm radiation were reported at the
intensities of 3× 1013 W/cm2, which led to the enormous growth of the interest in this area of nonlinear optics. The studies described
in this chapter demonstrate that application of ablated plasma
as a nonlinear medium can further amend this HHG technique
using picosecond driving pulses, once the atoms, ions, and clusters
become involved as the efficient sources of harmonic generation.
