
April 25, 2014 11:1 PSP Book - 9in x 6in 06-Rashid-A.-Ganeev-c06
High-Order Harmonic Cutoff Frequency in Atomic Silver Irradiated 191
the growth of harmonic order and the divergences of the lowest
(17th–25th) were approximately two to three times less compared
with the highest (45th–57th) harmonics.
At these experimental conditions (focusing inside the plasma
plume, intensity of the driving pulse at the plasma area I
fs
= 4 ×
10
14
W/cm
2
, delay between the pulses of 30 ns), the divergence
of driving radiation was changed by introducing the aperture in
front of the input window of vacuum chamber through which
femtosecond radiation propagated toward the plasma ...