Contrast in the coronagraphic images with the ZWFS control loop for different field stops. Top: Normalized azimuthal averaged intensity profile of the coronagraphic images produced with the ZWFS wavefront control in open loop (dashed line) and closed loop (solid line) as a function of the angular separation for a field stop size of 49 λ/D (purple) and 35 λ/D (red). The grey area with dashed line delimits the projected FPM size. The AO residuals are based on the VLT/SPHERE characteristics with a 6-mag natural guide star and median observing conditions with 10 m s⁻¹ windspeed and 0.7″ seeing. In closed loop, the ZWFS-based second-stage AO controls 350 KL modes and runs with an integrator using a loop gain of 0.8. Bottom: Contrast gain provided by the ZWFS-based wavefront control between the open and closed loop operations for different field stop sizes.