For effective S/N σ_i = 1, 10, and 100, closed-loop residual variances (top panels) and resulting δk_crit autocorrelation of the measurements (bottom panels) as a function of the loop gain α_iG_i from 0 up to g_crit. The latency is taken as τ = 2.T. Black lines show the total residual variance normalized to 1 at its minimum, blue represents the variance induced by turbulence , and green shows the variance induced by noise .