  We create a dark optical lattice structure using a blue detuned laser field
coupling an atomic ground state of total angular momentum F simultaneously to
two excited states with angular momenta F and F-1, or F and F+1. The atoms are
trapped at locations of purely circular polarization. The cooling process
efficiently accumulates almost half of the atomic population in the lowest
energy band which is only weakly coupled to the light field. The populations of
the two lowest energy bands reaches 70%. Kinetic energies on the order of the
recoil energy are obtained by adiabatically reducing the optical potential. The
band populations are directly mapped on free particle momentum intervals by
this adiabatic release. In an experiment with subrecoil momentum resolution we
measure the band populations and find good absolute agreement with the
theoretically calculated steady state band populations.
