We have theoretically investigated the focusing of a launched cloud of cold atoms. Time-dependent spatially-varying magnetic fields are used to impart impulses leading to a three-dimensional focus of the launched cloud. We discuss possible coil arrangements for a new focusing regime: isotropic 3D focusing of atoms with a single magnetic lens. We investigate focusing aberrations and find that, for typical experimental parameters, the widely used assumption of a purely harmonic lens is often inaccurate. The baseball lens offers the best possibility for isotropically focusing a cloud of weak-field-seeking atoms in 3D.

We have theoretically investigated 3D focusing of a launched cloud of cold atoms using a pair of magnetic lens pulses (the alternate-gradient method). Individual lenses focus radially and defocus axially or vice-versa. The performance of the two possible pulse sequences are compared and found to be ideal for loading both 'pancake' and 'sausage' shaped magnetic/optical microtraps. It is shown that focusing aberrations are considerably smaller for double-impulse magnetic lenses compared to single-impulse magnetic lenses. An analysis of the clouds focused by double-impulse technique is presented.

Single-impulse three-dimensional magnetic focusing of vertically launched cold atoms has been observed. Four different configurations of the lens were used to vary the relative radial and axial focusing properties. Compact focused clouds of 85 Rb were seen for all four configurations. It is shown that an atom-optical ray matrix approach for describing the lensing action is insufficient. Numerical simulation using a full approximation to the lens's magnetic field shows very good agreement with the radial focusing properties of the lens. However, the axial (vertical direction) focusing properties are less well described and the reasons for this are discussed.

We propose the novel combination of a laser guide and magnetic lens to transport a cold atomic cloud. We have modelled the loading and guiding of a launched cloud of cold atoms with the optical dipole force. We discuss the optimum strategy for loading typically 30 % of the atoms from a MOT and guiding them vertically through 22 cm. However, although the atoms are tightly confined transversely, thermal expansion in the propagation direction still results in a density loss of two orders of magnitude. By combining the laser guide with a single impulse from a magnetic lens we show one can actually increase the density of the guided atoms by a factor of 10.

There has been dramatic progress recently in atomic physics. It is now routine at hundreds of laboratories worldwide to cool samples of atoms to microkelvin temperatures through a process called laser cooling. Bizarre as it may sound, it is possible to use lasers (which are usually associated with cutting and heating) to slow atoms from the jumbo-jet speed of a room temperature gas to a snail's pace. At these low temperatures exciting new physics is observed, and atoms are treated as waves. An overview of the physics principles that underlie this technique is given, as well as a few examples of recent progress in the emergent fields of atom optics and manipulation of coherent matter waves.