Misregistration in Adaptive Optics Systems

An adaptive optics (AO) system is most effective when there is a known alignment between the wave front sensor (WFS)and the deformable mirror (DM). Misregistration is the term for the unknown alignment between the WFS and DM. Misregistration degrades system performance and can make the system unstable. An AO system uses a reconstruction matrix to transform WFS measurements into DM commands. A standard AO system uses a model reconstruction matrix that assumes perfect registration between the WFS and DM. The object of this research is to mitigate the negative effects of misregistration by using offline WFS measurements to create the reconstruction matrix. To build the reconstruction matrix, each actuator on the DM is poked to a fixed amount, and then the resulting measurement on the WFS is recorded. Analytic studies of the model and measured matrices show that the measured matrix yields a more stable AO system. Additional simulations indicate that applying the measured matrix improves the overall system performance compared to that of the model reconstruction matrix.