Improving the discovery potential of future light-shining-through-a-wall experiments

Planning for the next generation of light-shining-through-wall experiments has started. It is therefore timely to investigate possible ways to optimize their setups. The goals are to improve the sensitivity towards smaller couplings and increase the mass range to which the experiments are sensitive. We discuss possible magnet arrangements and the effects of the unavoidable gaps in the magnetic field profile. Furthermore, we discuss requirements on the diameter of the laser beam and aperture of the magnets in order to achieve high-quality cavities. (orig.)