QUANTUM-CONFINED FANO INTERFERENCE

We study the transition from a dense continuum to a sparse quasicontin uum in the Fano problem. Transmission measurements on epitaxial layers of GaAs in a high magnetic field and calculations of the optical abso rption show how the Fano interference disappears as quantum confinemen t discretizes the continuum states. The transition between quasi-one-d imensional and quasi-zero-dimensional systems occurs at length scales which are unusually large for optical experiments.