Stark ladders in strongly coupled superlattices and their interactions with embedded quantum wells

We have observed the formation of Stark ladders at low electric fields in a strongly coupled GaAs/${\mathrm{Al}}_{0.3}$ ${\mathrm{Ga}}_{0.7}$As superlattice, with miniband widths on the order of the conduction- and valence-band discontinuities. We deduce, for the first time, the energies of the Stark states for electrons, light holes, and heavy holes separately by examining optical transitions and anticrossings involving the Stark levels and the discrete levels of a pair of quantum wells embedded in the superlattice.