Controlling nonspreading wavepackets

We show how a static electric field can be used to control the localization of nonspreading wavepackets of a hydrogen atom driven by a linearly polarized microwave field. This allows for creation of wavepackets localized on fully stable resonance islands which, at the same time, can easily be excited by a direct optical transition from a low lying state. A semiclassical analysis is used to predict the energies and properties of such states