Optimization of optical traps using angular momentum

In this talk I will present our recent experimental and theoretical developments on the understanding of optical forces with structured light. Traditionally, the theoretical methods that have provided physical insight to the optical forces have been used in the small particle regime (dipolar physics) or very large particle regime (ray optics). Those regimes are not very useful when using complex spatial or polarization patterns in the optical trap. The intermediate regime, using Mie scattering or multipolar decomposition of fields, provides an exact modelling of the experimental conditions, but provides expressions that are difficult to evaluate and understand. We have found that using helicity and the angular momentum of light we can provide a physical insight to the expressions to the optical forces, but also we can offer extremely sensitive experimental control of optical traps in all situations.