High-harmonic generation in molecules
Prof. Dr. Manfred Lein
(Universität Kassel)
17.06.2009
High harmonic radiation is emitted from atoms or molecules when they
are subjected to intense laser pulses. We investigate the influence of
molecular structure and dynamics on high-harmonic generation, with the
main focus on hydrogen molecules. As two complementary methods, we use
the strong-field approximation as well as the numerical solution of the
time-dependent Schrödinger equation for model systems. We show that
both the two-center structure and the nuclear motion are important for
understanding the yield of harmonics in deuterium molecules versus
hydrogen molecules. Furthermore, we study the dependence of the harmonic
phase on the molecular orientation. For an accurate description of the
phase near an intensity minimum of the harmonics, it is important to go
beyond the commonly used saddle-point approximation. The latter, for example, restricts the electron motion to the direction of the laser
polarization.