High harmonic generations by laser in xenon clusters

Surface plasmon resonance enhanced high harmonic generation of intense short pulse lasers in xenon clusters is investigated. A laser prepulse partially ionizes the cluster atoms, turning them into plasma balls. As the main pulse arrives, plasma electrons execute large amplitude oscillations, creating a space charge field much higher than the laser field at surface plasmon resonance. The bound electrons under this field move out of the ions and return back with large residual energy. On recombination, they produce high harmonics. The number of photons emitted by the xenon clusters per second per frequency interval decreases with the emitted photon frequency.