From Magnetic Mirrors to Atom Chips

Abstract

Following the advent of laser cooling and trapping techniques in the 1980s, a new exciting area of research, ‘atom chips’, has emerged in which sophisticated micronscale structures on planar substrates are produced utilizing the latest technological developments in lithography and nanofabrication. These complex microstructures produce tiny magnetic field configurations which can trap, cool, and manipulate ensembles of ultra-cold atoms in the vicinity of a surface. Scaling down the dimensions of atom trapping geometry offers extended possibilities for the production and control of Bose–Einstein condensates (BECs). Enormous progress on the generation of BECs and quantum degenerate Fermi gases, on-chip matter–wave interferometers, and integrated detectors has been made in the last few years. In the second section of this article we trace the historical evolution of this new field, from the first surface-based atom optical elements –magneticmirrors – to the present-day micro-fabricated structures on a substrate – atom chips. In Section 1.3 we present the basic principles of magnetic mirrors for cold atoms and describe different types of magnetic mirror. Section 1.4 describes the production of a BEC on a permanent magnetic film atom chip; the application of this atom chip to probe the topology of magnetic fields using RF spectroscopy and to study the adiabatic splitting of a BEC in a double well for sensing asymmetric potentials; and investigations of the spatially dependent relative phase evolution of a two-component BEC. Finally, in Section 1.5 we describe a permanent magnetic lattice on an atom chip for trapping and manipulating multiple arrays of ultra-cold atoms and quantum degenerate gases.