Focusing and scanning through scattering media in microseconds
Recent advances in computational wavefront shaping have made optical focusing through scattering media a reality. However, most current techniques are too slow to focus, much less image through dynamically changing living biological tissue, such as blood perfused neural networks, which can decorrelate in milliseconds. We introduce a phase control technique using programmable acoustic optic deflectors (AODs) that is orders of magnitude faster than existing wavefront shaping methods. It is based on sending an array of RF encoded beams through the medium and measuring the phases of all scattered beams simultaneously with a fast single pixel detector in just 10 ms. Using the AODs, we then phase conjugate the beams to form a spatio temporal focus. We also demonstrate two dimensional scanning of the focus on a sub millisecond time scale.