Lattice of microtraps for ultracold atoms based on patterned magnetic films

We have realized a two-dimensional permanent magnetic lattice of Ioffe-Pritchard microtraps for ultracold atoms. The lattice is formed by a single 300-nm magnetized layer of FePt, patterned using optical lithography. Our magnetic lattice consists of more than 15 000 tightly confining microtraps with a density of 1250 traps∕mm2. Simple analytical approximations for the magnetic fields produced by the lattice are used to derive relevant trap parameters. We load ultracold atoms into at least 30 lattice sites at a distance of approximately 10 μm from the film surface. The present result is an important first step toward quantum information processing with neutral atoms in magnetic lattice potentials.