  We address the problem of energy dispersion of radiation pressure accelerated
(RPA) ion beams emerging from a thin (solid) target. Two different acceleration
schemes, namely phase-stable acceleration and multi-stage acceleration, are
considered by means of analytical modelling and one-dimensional
particle-in-cell simulations. Our investigations offer a deeper understanding
of RPA and allow us to derive some guidelines for generating monoenergetic ion
beams.
