Figure 6.

Principle of iterative wavefront shaping. (a) A flat wavefront incident on a scattering sample results in a speckle pattern to be observed at a detector placed behind the medium. (b) The phase of individual segments of the incident wavefront can be manipulated using an SLM. Due to the linearity of propagation, the phase of the respective contributions to the scattered field shifts accordingly. A high intensity at an arbitrarily chosen target at the detector is observed if a high number of field contributions match in phase at this position. The wavefront shaping algorithm iteratively optimizes the phase pattern applied to the incident beam such that the intensity at the target is maximized. (c) A high-intensity focal spot on top of a speckle pattern results with the final optimized wavefront. Image from [8], with permission.