Video demonstration of the close-loop Asymmetric Pupil Fourier Wavefront Sensor used on SCExAO, based on the principles exposed in an earlier paper. At first, a static aberration is applied on one of the channels (#5) of the SCExAO DM, on top of a reasonable amount of dynamic turbulence on channel #0. About half way through the video, the wavefront control loop is closed. Using the science camera image alone for diagnostic, the loop applies a correction on channel #4 that counters the static aberration. The impact on the PSF is quite obvious.
Video sequence of on-sky data acquired by the internal science camera of the SCExAO instrument during a test of the APF-WFS.
Video demonstration of the iterative close-loop speckle nulling software running on SCExAO, in the presence of residual turbulence (modeled by a Kolmogorov phase screen) on a non-coronagraphic image. In this example 20 speckles are simultaneously tracked and probed by the algorithm. The curves in the bottom right corner show the interference function between the original speckle and the probes sent by the DM. Each interference function is modeled by a sinusoidal function whose phase gives the phase of the original speckle. A new DM shape is computed to destructively interfere with the original speckles. In a few iterations, we can observe in the raw image (top right corner) that the region probed by the DM is progressively cleared of static speckles induced by the diffractive structures of the pupil (spider arms + thick asymmetric arm used for the APF-WFS).