Dynamics of colloids in external potentials created by light fields

We experimentally create different potential energy landscapes using extended laser light fields, ranging from periodic patterns (laser fringes) to random patterns (speckle patterns). The dynamics of colloidal particles in these potential energy landscapes are followed by video microscopy. Diffusive as well as sub- and super-diffusive behavior can be observed with the extent of the different regimes depending on the specific situation, such as the shape and modulation amplitude of the potential but also the composition of particle mixtures and the particle concentrations. We will review our findings from different experimental conditions and compare the experimentally observed behavior to simulation and theoretical results.