Strong-field-ionization suppression by light-field control

In recent attempts to control strong-field phenomena such as molecular dissociation, undesired ionization sometimes seriously limited the outcome. In this work we examine the capability of quantum optimal control theory to suppress the ionization by rational pulse shaping. Using a simple model system and the ground-state occupation as the target functional, we show that optimal control generally leads to a significant suppression of the ionization, although the fluence and the pulse length are kept fixed. In the low-frequency regime the ionization is reduced mainly by avoiding high peaks in the intensity and thus preventing tunneling. In contrast, at high frequencies in the extreme ultravio…