Baldwin, Kenneth2015-12-130010-7514http://hdl.handle.net/1885/81273In this, the hundredth year since Einstein first postulated the existence of photons, the successful application of wave-particle duality to matter has seen an explosion of activity in the field of atom optics and Bose- Einstein condensation (BEC). This article provides a brief introduction to atom optics, illustrated with applications taken from experiments using helium atoms in long-lived (metastable) excited states. Metastable helium atoms store the greatest amount of energy (∼20 electron volts) in any atomic or molecular system. They behave like nano-hand grenades, making it easy to detect single atoms, opening up promising applications as well as fundamental studies of the quantum statistical properties of atomic systems.1 vol.application/pdfen-AU200510.1080/001075104123313327982015-12-11