  We examine single-frequency optical schemes for species-selective trapping of
ultracold alkali-metal atoms. Independently addressing the elements of a binary
mixture enables the creation of an optical lattice for one atomic species with
little or no effect on the other. We analyze a "tune-in" scheme, using
near-resonant detuning to create a stronger potential for one specific element.
A "tune-out" scheme is also developed, in which the trapping wavelength is
chosen to lie between two strong transitions of an alkali-metal atom such that
the induced dipole moment is zero for that species but is nonzero for any
other. We compare these schemes by examining the trap depths and heating rates
associated with both. We find that the tune-in scheme is preferable for Li-Na,
Li-K, and K-Na mixtures, while the tune-out scheme is preferable for Li-Cs,
K-Rb, Rb-Cs, K-Cs and 39K-40K mixtures. Several applications of
species-selective optical lattices are explored, including the creation of a
lattice for a single species in the presence of a phononlike background, the
tuning of relative effective mass, and the isothermal increase of phase space
density.
