Wavefront correction using spatially distributed guide stars

In this contribution we analyze the performance of non-invasive guide stars that enable correction of a whole laterally extended imaging path. The guide star interacts with the distortion and is then measured with a phase sensitive technique. The obtained information is used to determine a phase mask, which is displayed on a spatial light modulator located in the detection path. Our guide star technique enables to correct the distorted wavefront and to perform a measurement through a distortion, as if the distortion was absent. We show experimental results based on liquid crystal on silicon SLMs and digital holography, give the theoretical framework and discuss the applicability and limitations of our guide star approach. Especially the influence of the modulator in terms of pixel-size, pixel-count, bit-depth and refresh-rate are considered. We discuss the potential of different modulators with high spatial and temporal resolution, like a 10 mega pixel SLM with 3.7 µm pixel size and a ferroelectric 1 bit modulator with 1.7 kHz off-line and 400 Hz closed-loop refresh rates. Additionally, phase sensing approaches and strategies on real-time data processing on fpga are introduced.