This chapter presents methods and concepts relevant to finite element simulation of adaptive optical systems.
In an adaptive optical system, image motion and aberrations are reduced by moving and deforming one or more optical surfaces. Such adjustment may be made continuously to compensate for drifting or harmonic disturbances. Often times such adjustments are made in response to a measurement of the optical performance of the system. Figure 6.1 shows a schematic of an adaptive telescope in which aberrations caused by a turbulent atmosphere are corrected. Before reaching the image plane, some of the light is split into a wavefront sensor. Measurements from the wavefront sensor are sent to a controller that statistically predicts how the deformable mirror should be actuated to best correct the incoming aberrations. In such a system, the ability of the algorithm used to predict accurate control commands to best correct the induced aberrations is critical to the net optical performance. It is equally important, however, for the deformable mirror to be able to deform into shapes that will be required to correct the aberrations induced by the atmosphere. Therefore, predictions of the deformable mirror's performance are of great interest to engineers designing such a system.
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