Directed fluxes of positronium using pulsed travelling optical lattices

Abstract

The creation of directed fluxes of positronium atoms using the optical dipole force from short, pulsed travelling optical lattices has been studied. By exploiting the favourable polarizability-to-mass ratio of positronium it has been found that accelerations in excess of 1014g are possible. Simulations have been performed for several cases in which lattice beams capture a substantial fraction of a cloud of ground state ortho-positronium atoms, assumed to be characterised by an initial temperature of 300 K. We show that, using conventional laser sources, bunches of positronium atoms can be accelerated, well within the ortho-positronium vacuum lifetime of 142 ns, to a wide variety of kinetic energies in the eV to 100s of eV range and with well-defined energy spreads. The final kinetic energy of the positronium can be tuned using the laser intensity, the pulse duration or the rate of change of the frequency between the two beams which form the lattice.