Tightly confining waveguide for cold atom interferometry

Summary form only given. The integration of atom optics components on a small surface may lead to many new experiments exploring the boundaries of quantum mechanics. Coherent transport of atoms is a key ingredient, and for this reason many groups are developing magnetic waveguides for cold atoms. So far the confinement in these guides is rather poor, resulting in the population of many transverse modes. Typically 10 Gauss over 100 /spl mu/m gives a mode spacing of 40 kHz for Cs atoms. We have developed a new magnetic waveguide, based on ferromagnetic material. At saturation the surface-field is 1 Tesla, which can be applied over a 10 /spl mu/m distance corresponding to a mode spacing of 18 MHz. We use a sandwich of mu-metal and copper sheets to generate a magnetic field. An electrical current of up to 5 A is running through the copper, encircling the mu-metal sheet. This induces an upward or downward field in the mu-metal, similar to a solenoid with a ferromagnetic core. Thin kapton sheets are used to provide electrical isolation.