Experimental laboratory results of closed-loop correction with the iMZ, a 12 × 12 DM, and for a full circular pupil. Left: evolution of the Strehl ratio for 20 iterations of the loop with a gain g = 0.3. The Strehl ratio measured with the optical transfer function (OTF) (dashed black line) is compared with the Maréchal approximation (solid purple line). The mismatch between the two curves comes from an underestimation of the phase (over estimation of the Strehl ratio) because some points of the input phase screen are higher than π/2 radians and the signal is wrapped. The four images under Strehl curves represent the PSFs (left) and the coronagraphic PSFs (right) for the first (up) and last iterations (down). Right: wavefronts measured by the iMZ (asymmetric output) for the first (up) and last iterations (down).