Optical Binding in Complex Landscapes

Optical binding occurs when light scattered from a microscopic particle induces forces on other microscopicparticles, which includes attractive, binding, forces. Since the original demonstration using dielectric spheres,there has been much interest in altering the shape and symmetry of the bound particles, leading to complexoptically driven behaviour typically involving uniform illumination in a restricted region e.g. an extended or linefocus or the axis of a Bessel beam. However, in the present computational study we consider confinement incomplex optical landscapes comprising one or many focussed beams. In this survey we will explore the behavioursof systems of spherical beads with various refractive indices, as well as systems of dimers, or dumbbells, consistingof pairs of linked spheres and active janus particles comprising pairs of beads with different refractive indices.The relative importance of optical trapping versus optical trapping between the particles will be assessed.