Precision optical trapping via a programmable direct-digital-synthesis-based controller for acousto-optic deflectors

We describe a simple-to-construct programmable direct-digital-synthesis-based controller for use with acousto-optic deflectors. Our controller corrects for nonlinear diffraction efficiency versus diffraction angle, provides superior stability, functionality, and configurability, and costs a fraction of commercially available systems. Using this instrument, we move a 1 mu m diameter bead by 1-nm-sized steps and resolve these steps.