The performances of high resolution magnetic deformable mirrors have been recently improved: the mechanical bandwidth has been increased to 2 kHz, and a fast stroboscopic Shack-Harman wavefront was used to measure a settling time as low as 400μs. Recent improvements in the substrate-thinning processes made possible the availability of large, high-quality membranes compatible with deformable mirrors. Prototype testing and simulations show that devices with up to 60x60 actuators are now possible. For open-loop operations, a novel feed-forward algorithm was developed to compensate for residual creeping and improve the DM stability to below10nm RMS over 6 hours.
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