The generation of high harmonics in laser–plasma interactions
on the steep density gradients is discussed, especially by using
short-pulse UV laser radiation. Low intensity experiments with
5·1015 W/cm2 generate harmonics in the
VUV range, and the efficiency can be optimized by modifying the density
gradient. To obtain higher harmonics and to clear some disagreements
among different results concerning polarization properties of harmonics
we switched for higher intensities. Our experimental arrangement makes
it possible to obtain a 5·1017 W/cm2
intensity with a prepulse as low as 107 W/cm2
using a table-top system. Preliminary results and future trends for
high-harmonics generation with this method are given.