Fig. 1: Unguided optimization.
a, Schematic of experimental set-up. An input wavefront is iteratively modified to reduce the output temporal intensity fluctuations. b, A plot of temporal fluctuation level (Fl) as a function of iteration number throughout the optimization procedure. Convergence plateaus (red dashed line) after ~2,500 iterations. c, Output intensity fluctuations for a randomly chosen input field. Upper heat maps show the mean intensity of transmitted light, and lower heat maps show the standard deviation of the intensity fluctuations. The line plots show line profiles through the output field along the lines marked with white hatched lines, with mean intensity (red line) and fluctuations about the mean (grey shading). Std., standard deviation. d, Equivalent plot to c but showing the suppressed output intensity fluctuations for an optimized input field. e, Measured shape of the optimized field inside the dynamic scattering sample. Top row: examples of the three phase planes forming the artificial scattering system, with a small fluctuating patch on each plane highlighted by a red box. Middle row: optimized optical field incident on each plane. Bottom row: corresponding intensity incident on each plane (max intensity on each plane is normalized to 1). We observe a low-intensity region on the three dynamic patches, highlighted by white arrows (percentage of intensity passing through each patch is quoted). The distance between the planes is δz = 5 cm. amp., amplitude; rad., radians; arb., arbitrary unit.
