A reflective microelectromechanical mirror array was used to control the intensity distribution of a coherent beam that was propagated through a strongly scattering medium. The controller modulated phase spatially in a plane upstream of the scattering medium and monitored intensity spatially in a plane downstream of the medium. Optimization techniques
were used to maximize the intensity at a single point in the downstream plane. Intensity enhancement by factors of several hundred were achieved within a few thousand iterations using a MEMS segmented deformable mirror (e.g. a spatial light modulator) with 1020 independent segments.
Increased temporal bandwidth is needed to accommodate scattering media with increased dynamics, including greater rates of bulk translation and eventually scatterers that evolve on a microscopic scale such as fog, smoke, or human tissue. In future work we plan to increase the temporal bandwidth of our adaptive system by using high-speed cameras and improved optimization algorithms.
