
85Self-Focusing and Nonlinear Effects
Chapter 4
3. For electron–hole plasma eects, the major absorption process is the one-photon
absorption due to electron–phonon–photon collisions in the conduction band.
Probability of the absorption scales linearly with laser irradiance, but density of the
absorbing particles (that are conduction-band electrons) starts with almost zero and
signicantly grows during the ionization process. erefore, the major contribution
to nonlinear scaling of R is done by the term n of Equation 4.3.
In the following, we consider each of the contributions to nonlinear absorption bearing in
mind that those three processes ...