  We study coherent quantum transport through a superconducting film connected
to normal-metal electrodes. Simple expressions for the differential conductance
and the local density of states are obtained in the clean limit and for
transparent interfaces. Quasiparticle interference causes periodic vanishing of
the Andreev reflection at the energies of geometrical resonances, subgap
transport, and gapless superconductivity near the interfaces. Application of
the results to spectroscopic measurements of the superconducting gap and the
Fermi velocity is analyzed.

Superconductivity