Dynamically controlled double-well optical potential for colloidal particles

This study presents a simple modulation scheme to dynamically create time-averaged optical potentials to trap colloidal particles using acousto-optical modulation. The method provides access to control experimentally relevant parameters of a tunable double-well potential. We show experimental data successfully adjusting the trapping distance in the range 20-2000 nm and discuss situations arising when reconstructing time-averaged optical potentials from trapped particle data. This is the first step towards studying colloidal particles in dynamically modulated optical potentials to explore the stochastic thermodynamics of mesoscopic systems and small-scale thermo-mechanical machines.