All-optical atom trap as a target for MOTRIMS-like collision experiments

Abstract

Momentum-resolved scattering experiments with laser-cooled atomic targets have been performed since almost two decades with magneto-optical trap recoil ion momentum spectroscopy (MOTRIMS) setups. Compared to experiments with gas-jet targets, MOTRIMS features significantly lower target temperatures allowing for an excellent recoil ion momentum resolution. However, the coincident and momentum-resolved detection of electrons was long rendered impossible due to incompatible magnetic field requirements. Here we report on an experimental approach which is based on an all-optical $^{6}\mathrm{Li}$ atom trap that---in contrast to magneto-optical traps---does not require magnetic field gradients in the trapping region. Atom temperatures of about 2 mK and number densities up to ${10}^{9}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ make this trap ideally suited for momentum-resolved electron-ion coincidence experiments. The overall configuration of the trap is very similar to conventional magneto-optical traps. It mainly requires small modifications of laser beam geometries and polarization which makes it easily implementable in other existing MOTRIMS experiments.