Tracing multiple scattering trajectories for deep optical imaging in scattering media

Multiple light scattering hampers imaging objects in complex scattering media. Approaches used in real practices mainly aim to filter out multiple scattering obscuring the ballistic waves that travel straight through the scattering medium. Here, we propose a method that makes the deterministic use of multiple scattering for microscopic imaging of an object embedded deep within scattering media. The proposed method finds a stack of multiple complex phase plates that generate similar light trajectories as the original scattering medium. By implementing the inverse scattering using the identified phase plates, our method rectifies multiple scattering and amplifies ballistic waves by almost 600 times. This leads to a significant increase in imaging depth—more than three times the scattering mean free path—as well as the correction of image distortions. Our study marks an important milestone in solving the long-standing high-order inverse scattering problems. Deep imaging in complex scattering media is hindered by multiple light scattering. Here, the authors proposed a method to trace multiple scattering trajectories in situ using a recorded reflection matrix and achieved enhanced imaging depth by converting these multiple scattering to signal waves.