
April 24, 2014 17:8 PSP Book - 9in x 6in 02-Rashid-A.-Ganeev-c02
28 Theoretical Basics of Plasma Harmonics
is due to phase matching and ionization. Often harmonics are
only produced in a very small temporal window when the phase
matching condition is met. Depletion of the generating media due to
ionization also means that harmonic generation is mainly confined
to the leading edge of the driving pulse. High harmonics are emitted
co-linearly with the driving laser and can have a very tight angular
confinement, sometimes with less divergence than that of the
fundamental field and near Gaussian beam profiles.
Some interesting limits on the HHG process, which ...