Within the framework of macroscopic quantum electrodynamics, the resonant van
der Waals potential experienced by an excited two-level atom near a planar
magneto-electric two-layer system consisting of a slab of left-handed material
and a perfect mirror is studied. It is shown that disregarding of material
absorption leads to unphysical results, with divergent values for the potential
away from the surface. Under appropriate conditions, the setup is found to
feature a barrier near the surface which can be employed to levitate particles
or used as a trapping or cooling mechanism. Finally, the problem of spontaneous
decay [J. K\"{a}stel and M. Fleischhauer, Phys. Rev. A \textbf{68}, 011804(R)
(2005)] is revisited. Disregarding of absorption is shown to drastically
falsify the dependence on the atomic position of the decay rate.Comment: 10 Pages, 6 figure